MESENCHYMAL HAMARTOMA OF THE CHEST WALL: A Cooperative Study with Review of the Literature
Marta C. Cohen, MD 0 Department of Pathology, Red Cross Children’s Hospital and University of Cape Town, Rondebosch, Cape Town, 7700 South Africa
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Ricardo Drut, MD, and Claudia Garcia, MD 0 Departamento de Patologia, Hospital de Niiios “Sor Maria Ludovica,” La Plata, Argentina Ronald 0. C. Kaschula, MMed(Path1 0 Department of Pathology, Red Cross Children’s Hospital and University of Cape Town, Rondebosch, Cape Town, 7700 South Africa
The clinicopathologic features of three examples of mesenchymal hamartoma of the chest wall are described. The entity has been recorded under a number of names including osteochondroma, osteochondrosarcoma, bent@ chondroblastoma, mesenchymoma, and chondromatow hamartoma. The condition is manifest at birth or shortly thereafter with deformity of the chest wall and respiratory distress. Radiographic examination reveals a well-defined, partly calcified mass involving one or more ribs. The tumor is composed predominantly of chondroid tissue with large endothelium-lined blood spaces and immature mesenchyme with osteoclastic giant cells and osteoid. We review the literature and sugest that the lesion should be distinguished j o m aneurysmal bone cyst, chondroma, and other mesenchymal neoplasms. In order to avoid local recurrence the recommended treatment is complete surgical resection. KEY WORDS: hamartoma, thoru.
INTRODUCTION Mesenchymal hamartoma of the chest wall (MHCW) is a distinct entity that is manifest at birth or shortly thereafter with characteristic clinical, radiographic, and pathological features. The lesion originates from one or more adjoining ribs with an extrapleural growth pattern. Dr. Osvaldo Gimenez of Santa Rosa (Argentina) referred case 1 to us (R.D.) and Dr. Hugh H . €3. Morris of Pietermaritzburg (South Africa) did the autopsy on case 3 and referred the material to us (R.K.). This study is supported by the Cancer Research Trust Fund of the University of Cape Town. Address reprint requests to: Prof. R. 0. C . Kaschula, Department of Pathology, Red Cross Children’s Hospital, Rondebosch, 7700 South Africa. Pediatric PatholoD, 12:525-534, 1992 Copyright @ 1992 by Hemisphere Publishing Corporation
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Fewer than three dozen cases have been reported in the literature. In most cases the entity was called osteochondroma (1, 2), osteochondrosarcoma (3), benign chondroblastoma (4), mesenchymoma (5-a), or chondromatous hamartoma (9). We wish to record our experience with this lesion as the result of a cooperative study of three cases from two referral centers. We review the literature to gain a better understanding of the condition and its diagnosis, treatment, and complications. We also suggest that the entity may occur more frequently than has been reported.
MATERIALS AND METHODS Two surgical specimens of MHCW were retrieved from the files of the Pathology Department of the Children’s Hospital “Sor Maria Ludovica,” La Plata, Argentina (cases 1 and 2). One postmortem examination of a baby with MHCW (case 3) at the Pathology Department of Red Cross War Memorial Children’s Hospital was also retrieved for the purpose of this cooperative study. The tissues were fixed in 10% formalin. Sections of paraffin-embedded tissue were stained with hematoxylin and eosin and Masson trichrome stains.
CASE REPORTS Case 1 A 3-day-old male infant presented with cyanosis and a tumor on the left thoracic wall. Computed tomography showed a well-defined round mass with irregular calcification. The lesion involved the posterior part of the eighth left rib. A surgical biopsy was performed and the diagnosis of MHCW was made. A pneumothorax occurred as a complication of the procedure. When the patient was 26 days old, surgical resection was performed. He is now alive and well after 9 years, but we do not know the status of his chest wall as the patient returned to a remote rural area.
Case 2 A 2-month-old female presented with a tumor on the left thoracic wall. A chest radiograph showed a partially calcified mass arising from the sixth and seventh ribs. No respiratory symptoms were noted. The lesion was surgically removed and the patient is alive and well a year after surgery.
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Case 3
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A term male infant with a deformed thorax was the product of an uneventful pregnancy. He survived for a few hours and died from severe respiratory distress. A tumoral lesion was observed arising from the right costal margin and lateral chest wall. An autopsy was performed, and material was referred to one of us (R.K.) and initially diagnosed as a complex congenital neoplasm.
MORPHOLOGIC FINDINGS The three tumors were all lobulated, well circumscribed, and arose from the ribs. The lesions from cases 1 and 2 measures 7 X 5 X 5 cm and 5 X 4 X 4 cm, respectively. The third tumor involved several ribs and occupied approximately 80% of the right hemithorax. It was composed of a large nodular mass with additional smaller discontinuous nodules suggesting a multicentric origin. The heart and right lung were distorted and displaced to the left. The right lung was hypoplastic, weighing 7.5 g (expected weight 25 g). The cut surface of all the tumors had a glistening multicystic appearance (Fig. 1). Some of the cysts were filled with blood. The remaining areas showed waxy to slightly gritty cartilaginous tissue and a variable amount of friable stroma. The tumors were composed predominantly of chondroid tissue with some
-
FIGURE 1. The cut surface of lobulated tumor (case 2) shows a multicystic appearance and attachment to the rib. Marker
2 cm.
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islands of hyaline cartilage undergoing ossification (Fig. 2). A prominent feature in all cases was a telangiectatic vascular component with hemosiderin-
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laden macrophages and osteoclastic giant cells resembling aneurysmal bone cyst (Fig. 3). Areas of immature spindle cells with some collagen formation were interspersed throughout the lesion (Fig. 4). No pleomorphism or abnormal mitotic activity was present in any of the cases. All tumors were surrounded by an incomplete fibrous capsule. DISCUSSION Mesenchymal hamartoma of the chest wall is a condition that is manifest at birth or shortly thereafter. The clinical presentation is that of a variable deformity of the thoracic wall with or without associated features of respiratory distress. Chest radiographs and computed tomography indicate a uni- or multifocal origin in one or more ribs with irregular soft tissue calcification. The deformity has generally been regarded as a mesenchymoma in the literature (5-8). In 1948 Stout (10) proposed the concept of mesenchymoma to refer to a group of neoplasms composed of two or more mesenchymal tissues that are not ordinarily found together (11). In their report of two cases of MHCW Blumenthal and co-workers in 1972 (5) used Stout’s diagnostic criteria and called their lesion a malignant mesenchymoma, although both their patients were well and disease free long after diagnosis and resection.
FIGURE 2. Hyaline cartilage and chondroid tissue are undergoing ossification (arrow) (case 3).
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FIGURE 3. Hyaline cartilage is in continuity with a telangiectatic vascular component associated with osteoclastic giant ceUs (arrow), resembling an aneurysmal bone cyst (case 3). X32.
FIGURE 4. Immature mesenchymal spindle cells form a significant component of the tumor (case 3). X63.
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Prior to being named mesenchymoma, this lesion had been called osteochondroma (1), osteochondrosarcoma (3), or atypical benign chondroblastoma (4). In 1979 McLeod and Dahlin (8) suggested that the lesion was a selflimiting nonneoplastic developmental anomaly with a curious but characteristic mixture of proliferating elements. They called this unique lesion a hamartoma. In our evaluation of the descriptions of the cases reported as osteochondroma (1, 2), osteochondrosarcoma (3), atypical benign chondroblastoma (4), and malignant mesenchymoma (5), we, like other authors (8, 9, 12-14), conclude that the cases are likely to be examples of MHCW and include them in our review. Table 1 shows the 33 cases of MHCW that we have been able to cull from the literature. The lesion characteristically presents at birth or in early infancy. An exception is found in the case reported by Conlan et al. (9) of a 13year-old black female. His explanation was that in the patient’s particular South African population group there is traditional reluctance to seek early medical treatment. Two of the previously reported cases (8, 17) were diagnosed in utero. Brar et al. (17) described the lesion in their case as a highly echogenic intrathoracic mass with calcified areas in a fetus during the third trimester of gestation. Their antenatal diagnosis contributed to effective early management. MHCW appears to arise from one or more ribs. Usually the lesion progressively enlarges extrapleurally and thus distorts the lungs and mediastinum as it grows to fill much of the thoracic cage. Our case 3 and McLeod and Dahlin’s (8) case were infant boys who suffered respiratory death soon after birth. In both cases death was caused by the MHCW that almost completely filled the hemithorax. In our case the ipsilateral lung was hypoplastic, probably because of early onset and growth of the tumor during intrauterine development. Three tumors have been reported (5, 15, 18) that were diagnosed but not resected, and none of these lesions has regressed but all have grown with the children. This suggests that there is a variable growth potential that is usually rapid to start with but can also be slow in some cases. The fact that our case 3 was multicentric and the reports of discontinuous unilateral (18) or bilateral (13) disease together with frequent involvement of more than one rib suggest that there may be a field aberration during early embryonic life that precedes the development of the lesion. Adding our 3 cases to those reported in the literature, we find that 15 lesions occurred in the left hemithorax, 18 in the right, and 3 bilaterally. The radiographic appearance of MHCW is that of a well-defined and partly calcified mass arising from one or more ribs. Histologically the lesions have a chondroid appearance with many vascular spaces lined by endothelium and filled with pools of blood. Osteoclastic giant cells, hyaline cartilage, immature spindle cells, and areas undergoing ossification are also often present.
MHCW MHCW MHCW
34 35 36
Cohen
"Except for c h a t wall deformity. 'Except for scvcre scoiioais.
MHCW Cartilaginous hamartoma Chest wall hamartoma MHCW
30
+
31 32 33
MHCW
29
18 19 20 21 22 23 24 25 26 27 28
Osteochondrosarcoma Congenital atypical benign chondrohlastoma Malignant mesenchymoma Malignant mcsenchymoma Malignant mesenchymoma Infantile ostcochondroma Chest wall mesenchymorna Chest wall hamartoma (mesenchymoma) Chest wall hamartoma (mcsenchymoma) Cheat wall hamartoma Chest wall hamartoma Chert wall hamartoma Chest wall hamartoma Chest wall hamartoma Chest wall hamartoma Chest wall hamartoma Vascular canilaginous hamartoma Vascular cartilaginous hamartoma aneurysmal bone cyst Ost-hondroma Benign mesenchymoma of chest wall Benign mesenchymoma of chest wall Benign mesenchymoma of chest wall Giant chondromatous hamartoma MHCW MHCW MHCW MHCW
Bilateral osteachondmma
Diagnosis
Petersen and Wykoupil (16) Brar et al. (17) Oaklcy et al. (18)
Brand ct al (13)
Conlan et al. (9) O d d and Benjamin (14)
Campbell et al. (15)
McCarthy and Dorfman (12)
Mayer et al. (6) Seibert et al. (2) W e s i n g e r et al. (7) M c h d and Dahlin (8)
Blumenthal et al. ( 5 )
16 17
2 3 4 5 6 7 8 9 10 I1 12 13 14 15
Hall and Ellison (3)
Kadd et al. (4)
1
Case
Hopkini and Freitas (1)
Author
TABLE 1. Site
L L
R SEYeral
M F M
M M M M
L L R L
F
M M M M M M F F F M F
F
M M F M M M M M M M F F F F M
M
LandR
R
L R R R L R RandL R R
R
L R R L R R L
L L
L L R R L R R
RandL
Many 4-7 9 8 6-7
L: 6-9 R: 2-6 4-5 3-5
Many Many 3-5 Several
1
7-8 5-6 4-12 4-7
4
Many 7-8 6-7 5-6 4 2-5 5-7 9-10
Many 7-10 9-10 7-8 ? 9-1 1 8-11
R . 4-8 L: many 7-10 8-10
Ribs involved
Birth 2 mo Birth
6wk
Birth Birth Fetus
Birth
Birth Birth 3mo 4 yr Birth Birth 5mo Fetus Birth Birth Birth 7mo Birth Birth 1 ma 7mo 7mo 4mo Birth Birth 1 yr 2mo 13 yr Birth Birth Birth Birth
2mo
Yes
Yes-late onset Yes No Yes
No Yes
-
Resection Resection Resection Resection of one of two lesions Resection Resection
Resection
Yes
No
Yes No No Yes No No
?
Yes ?
7
7
Yes Yes NO Yes
+ chemotherapy
+ chemotherapy
Resection Resection Resection Resection Resection Resection Resection Resection Resection Chemotherapy Resection None Resection Resection Resection Resection Resection
No NO ? ? Yes ?
-
Resection Resection None Resection Resection Resection Resection Resection Resection
No NO Yes Yes
No
Resection
Treatment
Yes
Age at Respiratory Sex diagnosis distress
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Wcll after 9 yr Well after 1 yr Died
Well after 2 yi
Recurrence Well -
well after I-1R yr Well after 3 yr Well after 6 y P Wd Well after 20 mo Well after 14 mo Well well after 1 y P Well after 2 yr but with recurrence Well after 1 yr
-
Well after 18 yr Well after 14 mo Well hut brain damaged
-
-
Well after 8-1R yrb Well after 3-112 yr Died WcUb Well after 5 mo Well after 16 yr
Well after 5 yr Well after 1-IR yr
-
Well after 6 yr Well after 10 moa Well after 16 yr
Well after 1 yr
Follow-up
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The most important and difficult diagnostic differentiation is from aneurysmal bone cyst (ABC). Almost 85% of ABCs become manifest during the first two decades of life (19) but are infrequent in the newborn. They have blood-filled spaces with thin fibrous trabeculae, giant cells, hemosiderin, and osteoid (20). The presence of cartilage, which is often immature, together with the very young age of the patient can help to differentiate MHCW from ABC. The fact that some ABCs occur in association with other lesions, such as hemangioma (2 1), fibrous dysplasia (22, 23), chondromyxoid fibroma (23, 24), benign chondroblastoma (25, 26), and nonossifying fibroma (23), introduces controversy about the nature of the vascular component of MHCW. One cannot confidently determine whether or not the variety of components indicates an association of separate lesions or a range of expression in a single aberration. Hemodynamic factors have been implicated in the development of secondary ABC (27). It is possible that the telangiectatic areas resembling ABC seen in the MHCW represent a superimposed secondary phenomenon. Lack of cytologic evidence of malignancy helps to differentiate the lesion from a chondrosarcoma or osteosarcoma. None of the tumors thus far reported have developed metastatic disease. Only two (13) have been reported to have recurred and in both patients the initial resection was incomplete. Of the 36 patients with MHCW, only 2 have died from respiratory distress attributed to the tumor. Twenty-eight patients underwent surgical resection alone, two patients had surgical excision followed by chemotherapy, and in two cases no treatment was given. One patient with two ipsilateral lesions (16) had surgical resection of the larger tumor but no treatment was administered to the smaller. Only two recurrences, due to incomplete initial resection, have been observed in this series (13): case 28 had a local recurrence within a year of initial surgery. A more extensive resection was then undertaken, but the patient has been lost to follow-up. Case 30 had a local recurrence at 2 years and no further treatment was given. Twenty-three of the 36 identified cases have been followed up for periods of 5 months to 18 years (mean 4.6 years), and except for the 2 recurrences mentioned above, all the patients were well and without evidence of malignant behavior. One patient (case 3) suffered from chest wall deformity and four (nos. 9, 12, 22, and 27) have developed severe scoliosis after surgical resection. Mesenchymal hamartoma of the chest wall is now a well-recognized entity that is manifest at birth or in early infancy with deformity of the thoracic wall and varying grades of respiratory distress. The lesion arises from one or more ribs and has a progressive extrapleural pattern of growth. The behavior is that of a benign lesion but complete surgical resection is recommended as local regrowth has been reported in two incompletely resected lesions. It is likely that some examples of this lesion are still being diagnosed as chondromatous
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tumors or aneurysmal bone cyst and that the 36 reported cases are probably not a reflection of the true incidence.
1 . Hopkins SM, Freitas EL. Bilateral osteochondroma of the ribs in an infant: An unusual cause of cyanosis. J Thorac Cardiovasc Surg 1965;49:247-9. 2. Seibert JJ, Rossi NP, McCarthy EF. A primary rib tumor in a newborn. J Pediatr Surg 1976;11:10312. 3. Hall DP, Ellison RG. Osteochondrosarcoma of the chest wall in a newborn infant: A case report six years after surgery. Am Surg 1964;30:745-7. 4. Kadell BM, Coulson WF, Desilets DT, Fonkalsrud EW. Congenital atypical benign chondroblastoma of a rib. J Pediatr Surg 1970;5:46-52. 5. Blumenthal BI, Capitanio MA, Queloz JM, Kirkpatrick JA. Intrathoracic mesenchymoma: Observation in two infants. Radiology 1972;104:107-9. 6. Mayer CM, Favara BE, Holton CP, Rainer WG. Malignant mesenchymoma in infants. Am J Dis Child 1974;128:847-50. 7. Schlesinger AE, Smith MB, Genez BN, McMahon DP, Swaney JJ. Chest wall mesenchymoma (hamartoma) in infancy: C T and M R findings. Pediatr Radiol 1989;19:212-3. 8. McLeod RA, Dahlin DC. Hamartoma (mesenchymoma) of the chest wall in infancy. Radiology 1979;131 :657-61. 9. Conlan AA, Hurwitz SS, Gritzman MC. Giant chondromatous hamartoma of the first rib: A case report. S Afr Med J 1982;62:703-4. 10. Stout AP. Mesenchymoma, the mixed tumor of mesenchymal derivatives. Ann Surg 1948; 127:278-90. 1 1 . Le Ber MS, Stout AP. Benign mesenchymomas in children. Cancer 1962;15:598-605. 12. McCarthy EF, Dorfman HD. Vascular and cartilaginous hamartoma of the ribs in infancy with secondary aneurysmal bone cyst formation. Am J Surg Pathol 1980;4:247-53. 13. Brand T, Hatch EI, Schaller RT, Stevenson JK, Arensman RM, Schwartz MZ. Surgical management of the infant with mesenchymal hamartoma of the chest wall. J Pediatr Surg 1986;21:556-8. 14. Ode11 JM, Benjamin DR. Mesenchymal hamartoma of chest wall in infancy. Natural history of two cases. Pediatr Pathol 1986;5:135-46. 15. Campbell AN, Wagget J, Mott MG. Benign mesenchymoma of the chest wall in infancy. J Surg Oncol 1982;21:267-70. 16. Petersen C , Wykoupil K. Cartilaginous hamartoma of the thoracic wall in a newborn infant. Neoplasms in a newborn. Z Kinderchir 1989;44:119-21. 1 7 . Brar MK, Cubberley DA, Baty BJ, Branch DW. Chest wall hamartoma in a fetus. J Ultrasound Med 1988;7:217-20. 18. Oakley RH, Carty H, Cudmore RE. Multiple benign mesenchymomata of the chest wall. Pediatr Radiol 1985;15:58-60. 19. Ruiter DJ, Van Rijssel TG, van der Velde EA. Aneurysmal bone cysts: A clinicopathologic study of 105 cases. Cancer 1977;39:2231-9. 20. Spjut HJ, Ayala AG. Skeletal tumors in children and adolescents. Hum Pathol 1983;14:628-42. 21. Dorfman HD, Steiner GC, Jaffe HL. Vascular tumors of bone. Hum Pathol 1971;2:349-76. 22. Buraczewski J, Dabska M. Pathogenesis of aneurysmal bone cyst. Relationship between the aneurysmal bone cyst and fibrous dysplasia of bone. Cancer 1971;28:597-604. 23. Donaldson WE J . Aneurysmal bone cysts. J Bone Joint Surg 1962;44A:25-40. Discussion: Jaffe JL. 40. 24. Rahimi A, Beabout JW, Ivins JC, Dahlin DC. Condromyxoid fibroma. A clinicopathologic study of 76 cases. Cancer 1972;30:726-36. 25. Dhalin DC, Ivins JC. Benign chondroblastoma. A study of 125 cases. Cancer 1972;30:401-13.
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26. Huvos AG, Marcove RC, Erlandson RA, Mike V.Chondroblastoma of bone. A clinicopathologic and electron microscopic study. Cancer 1972;29:760-71. 27. Biesecker JL, Marcove RC, Huvos AG, Mike V. Aneurysmal bone cysts. A clinicopathological study of 66 cases. Cancer 1970;26:615-25.
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Received October 25, 1991 Revision accepted January 5, 1992
Marta C. Cohen, MD 0 Department of Pathology, Red Cross Children’s Hospital and University of Cape Town, Rondebosch, Cape Town, 7700 South Africa
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Ricardo Drut, MD, and Claudia Garcia, MD 0 Departamento de Patologia, Hospital de Niiios “Sor Maria Ludovica,” La Plata, Argentina Ronald 0. C. Kaschula, MMed(Path1 0 Department of Pathology, Red Cross Children’s Hospital and University of Cape Town, Rondebosch, Cape Town, 7700 South Africa
The clinicopathologic features of three examples of mesenchymal hamartoma of the chest wall are described. The entity has been recorded under a number of names including osteochondroma, osteochondrosarcoma, bent@ chondroblastoma, mesenchymoma, and chondromatow hamartoma. The condition is manifest at birth or shortly thereafter with deformity of the chest wall and respiratory distress. Radiographic examination reveals a well-defined, partly calcified mass involving one or more ribs. The tumor is composed predominantly of chondroid tissue with large endothelium-lined blood spaces and immature mesenchyme with osteoclastic giant cells and osteoid. We review the literature and sugest that the lesion should be distinguished j o m aneurysmal bone cyst, chondroma, and other mesenchymal neoplasms. In order to avoid local recurrence the recommended treatment is complete surgical resection. KEY WORDS: hamartoma, thoru.
INTRODUCTION Mesenchymal hamartoma of the chest wall (MHCW) is a distinct entity that is manifest at birth or shortly thereafter with characteristic clinical, radiographic, and pathological features. The lesion originates from one or more adjoining ribs with an extrapleural growth pattern. Dr. Osvaldo Gimenez of Santa Rosa (Argentina) referred case 1 to us (R.D.) and Dr. Hugh H . €3. Morris of Pietermaritzburg (South Africa) did the autopsy on case 3 and referred the material to us (R.K.). This study is supported by the Cancer Research Trust Fund of the University of Cape Town. Address reprint requests to: Prof. R. 0. C . Kaschula, Department of Pathology, Red Cross Children’s Hospital, Rondebosch, 7700 South Africa. Pediatric PatholoD, 12:525-534, 1992 Copyright @ 1992 by Hemisphere Publishing Corporation
525
526
M. C. COHEN ET AL.
Fetal Pediatr Pathol Downloaded from informahealthcare.com by McMaster University on 10/30/14 For personal use only.
Fewer than three dozen cases have been reported in the literature. In most cases the entity was called osteochondroma (1, 2), osteochondrosarcoma (3), benign chondroblastoma (4), mesenchymoma (5-a), or chondromatous hamartoma (9). We wish to record our experience with this lesion as the result of a cooperative study of three cases from two referral centers. We review the literature to gain a better understanding of the condition and its diagnosis, treatment, and complications. We also suggest that the entity may occur more frequently than has been reported.
MATERIALS AND METHODS Two surgical specimens of MHCW were retrieved from the files of the Pathology Department of the Children’s Hospital “Sor Maria Ludovica,” La Plata, Argentina (cases 1 and 2). One postmortem examination of a baby with MHCW (case 3) at the Pathology Department of Red Cross War Memorial Children’s Hospital was also retrieved for the purpose of this cooperative study. The tissues were fixed in 10% formalin. Sections of paraffin-embedded tissue were stained with hematoxylin and eosin and Masson trichrome stains.
CASE REPORTS Case 1 A 3-day-old male infant presented with cyanosis and a tumor on the left thoracic wall. Computed tomography showed a well-defined round mass with irregular calcification. The lesion involved the posterior part of the eighth left rib. A surgical biopsy was performed and the diagnosis of MHCW was made. A pneumothorax occurred as a complication of the procedure. When the patient was 26 days old, surgical resection was performed. He is now alive and well after 9 years, but we do not know the status of his chest wall as the patient returned to a remote rural area.
Case 2 A 2-month-old female presented with a tumor on the left thoracic wall. A chest radiograph showed a partially calcified mass arising from the sixth and seventh ribs. No respiratory symptoms were noted. The lesion was surgically removed and the patient is alive and well a year after surgery.
MESENCHYMAL HAMARTOMA OF CHEST WALL
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Case 3
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A term male infant with a deformed thorax was the product of an uneventful pregnancy. He survived for a few hours and died from severe respiratory distress. A tumoral lesion was observed arising from the right costal margin and lateral chest wall. An autopsy was performed, and material was referred to one of us (R.K.) and initially diagnosed as a complex congenital neoplasm.
MORPHOLOGIC FINDINGS The three tumors were all lobulated, well circumscribed, and arose from the ribs. The lesions from cases 1 and 2 measures 7 X 5 X 5 cm and 5 X 4 X 4 cm, respectively. The third tumor involved several ribs and occupied approximately 80% of the right hemithorax. It was composed of a large nodular mass with additional smaller discontinuous nodules suggesting a multicentric origin. The heart and right lung were distorted and displaced to the left. The right lung was hypoplastic, weighing 7.5 g (expected weight 25 g). The cut surface of all the tumors had a glistening multicystic appearance (Fig. 1). Some of the cysts were filled with blood. The remaining areas showed waxy to slightly gritty cartilaginous tissue and a variable amount of friable stroma. The tumors were composed predominantly of chondroid tissue with some
-
FIGURE 1. The cut surface of lobulated tumor (case 2) shows a multicystic appearance and attachment to the rib. Marker
2 cm.
528
M. C. COHEN E l AL.
islands of hyaline cartilage undergoing ossification (Fig. 2). A prominent feature in all cases was a telangiectatic vascular component with hemosiderin-
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laden macrophages and osteoclastic giant cells resembling aneurysmal bone cyst (Fig. 3). Areas of immature spindle cells with some collagen formation were interspersed throughout the lesion (Fig. 4). No pleomorphism or abnormal mitotic activity was present in any of the cases. All tumors were surrounded by an incomplete fibrous capsule. DISCUSSION Mesenchymal hamartoma of the chest wall is a condition that is manifest at birth or shortly thereafter. The clinical presentation is that of a variable deformity of the thoracic wall with or without associated features of respiratory distress. Chest radiographs and computed tomography indicate a uni- or multifocal origin in one or more ribs with irregular soft tissue calcification. The deformity has generally been regarded as a mesenchymoma in the literature (5-8). In 1948 Stout (10) proposed the concept of mesenchymoma to refer to a group of neoplasms composed of two or more mesenchymal tissues that are not ordinarily found together (11). In their report of two cases of MHCW Blumenthal and co-workers in 1972 (5) used Stout’s diagnostic criteria and called their lesion a malignant mesenchymoma, although both their patients were well and disease free long after diagnosis and resection.
FIGURE 2. Hyaline cartilage and chondroid tissue are undergoing ossification (arrow) (case 3).
X
50.
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FIGURE 3. Hyaline cartilage is in continuity with a telangiectatic vascular component associated with osteoclastic giant ceUs (arrow), resembling an aneurysmal bone cyst (case 3). X32.
FIGURE 4. Immature mesenchymal spindle cells form a significant component of the tumor (case 3). X63.
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M. C. COHEN ET AL.
Prior to being named mesenchymoma, this lesion had been called osteochondroma (1), osteochondrosarcoma (3), or atypical benign chondroblastoma (4). In 1979 McLeod and Dahlin (8) suggested that the lesion was a selflimiting nonneoplastic developmental anomaly with a curious but characteristic mixture of proliferating elements. They called this unique lesion a hamartoma. In our evaluation of the descriptions of the cases reported as osteochondroma (1, 2), osteochondrosarcoma (3), atypical benign chondroblastoma (4), and malignant mesenchymoma (5), we, like other authors (8, 9, 12-14), conclude that the cases are likely to be examples of MHCW and include them in our review. Table 1 shows the 33 cases of MHCW that we have been able to cull from the literature. The lesion characteristically presents at birth or in early infancy. An exception is found in the case reported by Conlan et al. (9) of a 13year-old black female. His explanation was that in the patient’s particular South African population group there is traditional reluctance to seek early medical treatment. Two of the previously reported cases (8, 17) were diagnosed in utero. Brar et al. (17) described the lesion in their case as a highly echogenic intrathoracic mass with calcified areas in a fetus during the third trimester of gestation. Their antenatal diagnosis contributed to effective early management. MHCW appears to arise from one or more ribs. Usually the lesion progressively enlarges extrapleurally and thus distorts the lungs and mediastinum as it grows to fill much of the thoracic cage. Our case 3 and McLeod and Dahlin’s (8) case were infant boys who suffered respiratory death soon after birth. In both cases death was caused by the MHCW that almost completely filled the hemithorax. In our case the ipsilateral lung was hypoplastic, probably because of early onset and growth of the tumor during intrauterine development. Three tumors have been reported (5, 15, 18) that were diagnosed but not resected, and none of these lesions has regressed but all have grown with the children. This suggests that there is a variable growth potential that is usually rapid to start with but can also be slow in some cases. The fact that our case 3 was multicentric and the reports of discontinuous unilateral (18) or bilateral (13) disease together with frequent involvement of more than one rib suggest that there may be a field aberration during early embryonic life that precedes the development of the lesion. Adding our 3 cases to those reported in the literature, we find that 15 lesions occurred in the left hemithorax, 18 in the right, and 3 bilaterally. The radiographic appearance of MHCW is that of a well-defined and partly calcified mass arising from one or more ribs. Histologically the lesions have a chondroid appearance with many vascular spaces lined by endothelium and filled with pools of blood. Osteoclastic giant cells, hyaline cartilage, immature spindle cells, and areas undergoing ossification are also often present.
MHCW MHCW MHCW
34 35 36
Cohen
"Except for c h a t wall deformity. 'Except for scvcre scoiioais.
MHCW Cartilaginous hamartoma Chest wall hamartoma MHCW
30
+
31 32 33
MHCW
29
18 19 20 21 22 23 24 25 26 27 28
Osteochondrosarcoma Congenital atypical benign chondrohlastoma Malignant mesenchymoma Malignant mcsenchymoma Malignant mesenchymoma Infantile ostcochondroma Chest wall mesenchymorna Chest wall hamartoma (mesenchymoma) Chest wall hamartoma (mcsenchymoma) Cheat wall hamartoma Chest wall hamartoma Chert wall hamartoma Chest wall hamartoma Chest wall hamartoma Chest wall hamartoma Chest wall hamartoma Vascular canilaginous hamartoma Vascular cartilaginous hamartoma aneurysmal bone cyst Ost-hondroma Benign mesenchymoma of chest wall Benign mesenchymoma of chest wall Benign mesenchymoma of chest wall Giant chondromatous hamartoma MHCW MHCW MHCW MHCW
Bilateral osteachondmma
Diagnosis
Petersen and Wykoupil (16) Brar et al. (17) Oaklcy et al. (18)
Brand ct al (13)
Conlan et al. (9) O d d and Benjamin (14)
Campbell et al. (15)
McCarthy and Dorfman (12)
Mayer et al. (6) Seibert et al. (2) W e s i n g e r et al. (7) M c h d and Dahlin (8)
Blumenthal et al. ( 5 )
16 17
2 3 4 5 6 7 8 9 10 I1 12 13 14 15
Hall and Ellison (3)
Kadd et al. (4)
1
Case
Hopkini and Freitas (1)
Author
TABLE 1. Site
L L
R SEYeral
M F M
M M M M
L L R L
F
M M M M M M F F F M F
F
M M F M M M M M M M F F F F M
M
LandR
R
L R R R L R RandL R R
R
L R R L R R L
L L
L L R R L R R
RandL
Many 4-7 9 8 6-7
L: 6-9 R: 2-6 4-5 3-5
Many Many 3-5 Several
1
7-8 5-6 4-12 4-7
4
Many 7-8 6-7 5-6 4 2-5 5-7 9-10
Many 7-10 9-10 7-8 ? 9-1 1 8-11
R . 4-8 L: many 7-10 8-10
Ribs involved
Birth 2 mo Birth
6wk
Birth Birth Fetus
Birth
Birth Birth 3mo 4 yr Birth Birth 5mo Fetus Birth Birth Birth 7mo Birth Birth 1 ma 7mo 7mo 4mo Birth Birth 1 yr 2mo 13 yr Birth Birth Birth Birth
2mo
Yes
Yes-late onset Yes No Yes
No Yes
-
Resection Resection Resection Resection of one of two lesions Resection Resection
Resection
Yes
No
Yes No No Yes No No
?
Yes ?
7
7
Yes Yes NO Yes
+ chemotherapy
+ chemotherapy
Resection Resection Resection Resection Resection Resection Resection Resection Resection Chemotherapy Resection None Resection Resection Resection Resection Resection
No NO ? ? Yes ?
-
Resection Resection None Resection Resection Resection Resection Resection Resection
No NO Yes Yes
No
Resection
Treatment
Yes
Age at Respiratory Sex diagnosis distress
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Wcll after 9 yr Well after 1 yr Died
Well after 2 yi
Recurrence Well -
well after I-1R yr Well after 3 yr Well after 6 y P Wd Well after 20 mo Well after 14 mo Well well after 1 y P Well after 2 yr but with recurrence Well after 1 yr
-
Well after 18 yr Well after 14 mo Well hut brain damaged
-
-
Well after 8-1R yrb Well after 3-112 yr Died WcUb Well after 5 mo Well after 16 yr
Well after 5 yr Well after 1-IR yr
-
Well after 6 yr Well after 10 moa Well after 16 yr
Well after 1 yr
Follow-up
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M. C. COHEN ET AL.
The most important and difficult diagnostic differentiation is from aneurysmal bone cyst (ABC). Almost 85% of ABCs become manifest during the first two decades of life (19) but are infrequent in the newborn. They have blood-filled spaces with thin fibrous trabeculae, giant cells, hemosiderin, and osteoid (20). The presence of cartilage, which is often immature, together with the very young age of the patient can help to differentiate MHCW from ABC. The fact that some ABCs occur in association with other lesions, such as hemangioma (2 1), fibrous dysplasia (22, 23), chondromyxoid fibroma (23, 24), benign chondroblastoma (25, 26), and nonossifying fibroma (23), introduces controversy about the nature of the vascular component of MHCW. One cannot confidently determine whether or not the variety of components indicates an association of separate lesions or a range of expression in a single aberration. Hemodynamic factors have been implicated in the development of secondary ABC (27). It is possible that the telangiectatic areas resembling ABC seen in the MHCW represent a superimposed secondary phenomenon. Lack of cytologic evidence of malignancy helps to differentiate the lesion from a chondrosarcoma or osteosarcoma. None of the tumors thus far reported have developed metastatic disease. Only two (13) have been reported to have recurred and in both patients the initial resection was incomplete. Of the 36 patients with MHCW, only 2 have died from respiratory distress attributed to the tumor. Twenty-eight patients underwent surgical resection alone, two patients had surgical excision followed by chemotherapy, and in two cases no treatment was given. One patient with two ipsilateral lesions (16) had surgical resection of the larger tumor but no treatment was administered to the smaller. Only two recurrences, due to incomplete initial resection, have been observed in this series (13): case 28 had a local recurrence within a year of initial surgery. A more extensive resection was then undertaken, but the patient has been lost to follow-up. Case 30 had a local recurrence at 2 years and no further treatment was given. Twenty-three of the 36 identified cases have been followed up for periods of 5 months to 18 years (mean 4.6 years), and except for the 2 recurrences mentioned above, all the patients were well and without evidence of malignant behavior. One patient (case 3) suffered from chest wall deformity and four (nos. 9, 12, 22, and 27) have developed severe scoliosis after surgical resection. Mesenchymal hamartoma of the chest wall is now a well-recognized entity that is manifest at birth or in early infancy with deformity of the thoracic wall and varying grades of respiratory distress. The lesion arises from one or more ribs and has a progressive extrapleural pattern of growth. The behavior is that of a benign lesion but complete surgical resection is recommended as local regrowth has been reported in two incompletely resected lesions. It is likely that some examples of this lesion are still being diagnosed as chondromatous
MESENCHYMAL HAMARTOMA OF CHEST WALL
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tumors or aneurysmal bone cyst and that the 36 reported cases are probably not a reflection of the true incidence.
1 . Hopkins SM, Freitas EL. Bilateral osteochondroma of the ribs in an infant: An unusual cause of cyanosis. J Thorac Cardiovasc Surg 1965;49:247-9. 2. Seibert JJ, Rossi NP, McCarthy EF. A primary rib tumor in a newborn. J Pediatr Surg 1976;11:10312. 3. Hall DP, Ellison RG. Osteochondrosarcoma of the chest wall in a newborn infant: A case report six years after surgery. Am Surg 1964;30:745-7. 4. Kadell BM, Coulson WF, Desilets DT, Fonkalsrud EW. Congenital atypical benign chondroblastoma of a rib. J Pediatr Surg 1970;5:46-52. 5. Blumenthal BI, Capitanio MA, Queloz JM, Kirkpatrick JA. Intrathoracic mesenchymoma: Observation in two infants. Radiology 1972;104:107-9. 6. Mayer CM, Favara BE, Holton CP, Rainer WG. Malignant mesenchymoma in infants. Am J Dis Child 1974;128:847-50. 7. Schlesinger AE, Smith MB, Genez BN, McMahon DP, Swaney JJ. Chest wall mesenchymoma (hamartoma) in infancy: C T and M R findings. Pediatr Radiol 1989;19:212-3. 8. McLeod RA, Dahlin DC. Hamartoma (mesenchymoma) of the chest wall in infancy. Radiology 1979;131 :657-61. 9. Conlan AA, Hurwitz SS, Gritzman MC. Giant chondromatous hamartoma of the first rib: A case report. S Afr Med J 1982;62:703-4. 10. Stout AP. Mesenchymoma, the mixed tumor of mesenchymal derivatives. Ann Surg 1948; 127:278-90. 1 1 . Le Ber MS, Stout AP. Benign mesenchymomas in children. Cancer 1962;15:598-605. 12. McCarthy EF, Dorfman HD. Vascular and cartilaginous hamartoma of the ribs in infancy with secondary aneurysmal bone cyst formation. Am J Surg Pathol 1980;4:247-53. 13. Brand T, Hatch EI, Schaller RT, Stevenson JK, Arensman RM, Schwartz MZ. Surgical management of the infant with mesenchymal hamartoma of the chest wall. J Pediatr Surg 1986;21:556-8. 14. Ode11 JM, Benjamin DR. Mesenchymal hamartoma of chest wall in infancy. Natural history of two cases. Pediatr Pathol 1986;5:135-46. 15. Campbell AN, Wagget J, Mott MG. Benign mesenchymoma of the chest wall in infancy. J Surg Oncol 1982;21:267-70. 16. Petersen C , Wykoupil K. Cartilaginous hamartoma of the thoracic wall in a newborn infant. Neoplasms in a newborn. Z Kinderchir 1989;44:119-21. 1 7 . Brar MK, Cubberley DA, Baty BJ, Branch DW. Chest wall hamartoma in a fetus. J Ultrasound Med 1988;7:217-20. 18. Oakley RH, Carty H, Cudmore RE. Multiple benign mesenchymomata of the chest wall. Pediatr Radiol 1985;15:58-60. 19. Ruiter DJ, Van Rijssel TG, van der Velde EA. Aneurysmal bone cysts: A clinicopathologic study of 105 cases. Cancer 1977;39:2231-9. 20. Spjut HJ, Ayala AG. Skeletal tumors in children and adolescents. Hum Pathol 1983;14:628-42. 21. Dorfman HD, Steiner GC, Jaffe HL. Vascular tumors of bone. Hum Pathol 1971;2:349-76. 22. Buraczewski J, Dabska M. Pathogenesis of aneurysmal bone cyst. Relationship between the aneurysmal bone cyst and fibrous dysplasia of bone. Cancer 1971;28:597-604. 23. Donaldson WE J . Aneurysmal bone cysts. J Bone Joint Surg 1962;44A:25-40. Discussion: Jaffe JL. 40. 24. Rahimi A, Beabout JW, Ivins JC, Dahlin DC. Condromyxoid fibroma. A clinicopathologic study of 76 cases. Cancer 1972;30:726-36. 25. Dhalin DC, Ivins JC. Benign chondroblastoma. A study of 125 cases. Cancer 1972;30:401-13.
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26. Huvos AG, Marcove RC, Erlandson RA, Mike V.Chondroblastoma of bone. A clinicopathologic and electron microscopic study. Cancer 1972;29:760-71. 27. Biesecker JL, Marcove RC, Huvos AG, Mike V. Aneurysmal bone cysts. A clinicopathological study of 66 cases. Cancer 1970;26:615-25.
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Received October 25, 1991 Revision accepted January 5, 1992
