Rhabdomyosarcoma By J.J. Murphy,
Arising Within Congenital Report of Three Cases
G.K. Blair, G.C. Fraser, P.G. Ashmore,
Pulmonary
Cysts:
J.G. LeBlanc, S.S. Sett, P. Rogers, J.F. Magee, G.P. Taylor,
and J. Dimmick Vancouver,
British
Columbia
l Over the past 9 months, three cases of primary pulmonary rhabdomyosarcoma
have been treated at British Colum-
bia Children’s Hospital. Two patients (aged 24 and 37 months) presented with spontaneous
pneumothoraces
and had cystic
changes in the affected lung on chest radiograph. patient
(aged 42 months) was evaluated
The third
for chronic cough,
fever, and failure to thrive. Chest x-ray showed a large mass in the left lower lobe as well as mediastinal
adenopathy.
All
three of these lesions originated within congenital lung cysts, one a peripheral adenomatoid
bronchogenic
malformations.
is a significant
risk for the development
coma within malformed Copyright
cyst and the others
cystic
This report suggests that there of rhabdomyosar-
pulmonary tissue.
o 1992 by W.B. Saunders Company
INDEX WORDS:
Rhabdomyosarcoma,
pulmonary;
lung cyst,
congenital.
A
LTHOUGH rhabdomyosarcoma is an uncommon childhood malignancy, it is the most frequently encountered soft tissue sarcoma found in infants and children.’ The head and neck, extremities, genitourinary tract, and trunk are the most common primary sites, with metastatic lesions usually found in the lungs. Primary intrathoracic rhabdomyosarcomas are rare, and there have only been 13 reported cases of primary pulmonary lesions.‘-lo Although the majority of these have been endobronchial, several reports have documented the origin of the rhabdomyosarcoma within congenital pulmonary cystic lesions.1+5,6 In this report we describe three cases of primary pulmonary rhabdomyosarcoma that were encountered at this institution over the past 9 months. TWO of these neoplasms were found within cystic adenomatoid malformations, whereas the third originated within a peripheral bronchogenic cyst.
From the Divisions of Pediaftic General Surgery, Cardiothoracic Surgery, Oncology and Pathofogy, British Coiumbia Children’s Hospital, Vancouver, British Columbia. Presented at the 23rd Annual Meeting of the Canadian Association of Paediattic Surgeons, Quebec City, Quebec, September 19-22, 1991. Address reprint requests to James J. Murphy, MD, Section of Surgery-Room IL7 British Columbia Children’s Hospital, 4480 Oak St, Vancouver, BC V6H 3V4_ Canada. Copyright o 1992 by W B. Saunders Company 0022-3468192/2710-0031$03.00/O
1364
CASE REPORTS Case 1 A 2-year-old girl was in her usual state of good health until the day of hospital admission when she developed the acute onset of shortness of breath, tachypnea, and tachycardia. Chest radiograph showed a tension pneumothorax on the right. Chest tube was placed. Repeat chest x-ray demonstrated partial reexpansion of the lung as well as cystic changes at the right lung base. She was plagued by recurrent pneumothoraces requiring repeated chest tube placement. Computed tomography (CT) scan showed cystic lesions in the right lower lobe. The mediastinum and pleura were normal. Right thoracotomy and wedge resection of a cystic lesion involving right lower lobe was performed. Pathology report described a 7 x 5 x 2 cm multiloculated lesion. Embryonal rhabdomyosarcoma was found within a developmental (peripheral bronchogenic) cyst (Fig 1). The cyst itself appeared to be an outgrowth of a small focus of dysplastic lung. The tumor microscopically involved the pleura, although the proximal margin was clear. The patient made an uneventful recovery and was discharged on postoperative day 3. Metastatic workup was negative. Extent of disease was deemed to be stage II with microscopic residual disease in the pleural cavity. She was randomized to regimen 33 of the IRS-3 group 2 study. Chemotherapeutic protocol included Actinomycin D, Vincristine, and Adriamycin for 1 year. She did not receive radiation therapy. At 1 year postresection she has shown no evidence of recurrent or residual disease on follow-up CT scan.
Case
2
A 3-year-old girl was well until 3 weeks prior to admission when she developed a flu-like illness. On the day of admission she complained of the acute onset of cough, shortness of breath, and right-sided chest discomfort. Chest x-ray demonstrated a right tension pneumothorax (Fig 2). Chest tube was placed but air leak persisted for several days. CT scan showed cystic and solid nodular lesions involving the right middle and lower lobes (Fig 3). She subsequently underwent right middle and lower lobectomy. Pathology reports describe a 3.0 x 5.5 x 2.3 cm lesion with solid and large cystic components in the lower lobe. The middle lobe was involved to a lesser extent with a similar process. Embryonal rhabdomyosarcoma was found within a cystic adenomatoid malformation in botyroid fashion (Fig 4). Most of the cyst wall as well as the polypoid lesions within the cyst itself contained rhabdomyosarcoma. Embryonal rhabdomyosarcoma was present at the pleural surface of the cyst in a few areas, including the point of rupture of
the dominant cyst. Her postoperative
course was complicated by recurrent pneumothoraces and persistent air leak which eventually resolved. Although she technically had stage II disease with microscopic residual, she was treated with the group III IRS CCG71 regimen C. This includes Vincristine, Ifofamide, and VP-16 every 3 weeks for 1 year. She did not receive adjuvant radiation therapy. Recent evaluation 3 months after resection has not identified any residual or recurrent disease.
JournalofPediatricSurgery,
Vol27, No 10 (October), 1992: pp 1364-1367
RHABDOMYOSARCOMA
IN CONGENITAL
PULMONARY CYSTS
Fig 1. Intact cuboidal and columnar pseudostratified epithelium of cyst lining (see arrows) with rhabdomyosarcoma adjacent to it. (Original magnification x40.)
Case 3 A 3’/z-year-old boy presented with a several-month history of failure to thrive, lethargy, fever, cough, and iron deficiency anemia. Chest radiograph demonstrated a large mass involving the left lower lobe. The mass was compressing the mediastinum and deviating it to the right. CT scan confirmed the presence of this mass and also showed hilar adenopathy (Fig 5). Left thoracotomy was performed with resection of the left lower lobe. Hilar and intralobar lymph nodes were involved. Pathology demonstrated a 10 x 10 x 9 cm vascular soft tissue mass. The histology showed a rhabdomyosarcoma originating within a cystic adenomatoid malformation. There was complete replacement of the cyst wall with primitive rhabdomyomatous elements (Fig 6). Tumor penetrated viscera1 pleura and hilar lymph nodes contained metastatic tumor. He made an uneventful recovery from surgery. Clinically his extent of disease was stage IIB with nodal disease. He was started on the group II IRS protocol receiving Vincristine every 3 weeks
Fig 2.
Right tension pneumothorax
due to cyst rupture.
Fig 3. Cystic and solid components of rhabdomyosarcoma ing right middle and lower lobes.
involv-
for 1 year. Recent evaluation 6 months postresection has failed to identify residual or recurrent disease. DISCUSSION
Despite the well-documented fact that primary pulmonary rhabdomyosarcoma is an extremely rare lesion, we have evaluated and treated three cases over the past 9 months. To date, only 13 cases of this neoplasm have been reported in the pediatric age group.l-lo Only 3 of the 646 children registered with the Intergroup Rhabdomyosarcoma Study had primary pulmonary lesions.3 Allan et al7 and Hartmann et al9 both documented two cases, while the others were all single case reports. Two of the three patients were essentially asymptomatic until development of spontaneous tension pneumothorax. In reviewing the previous reports, 22% (2/9) of the children presented with a similar picture, while 67% (6/9) complained of fever and
Fig 4. Lung cyst with botyroid invasion of rhabdomyosarcoma. Mucosal lining of cyst (see arrow) with rhabdomyablasts impinging on it and beginning invasion. (Original magnification x 100.)
MURPHY ET AL
1366
Fig 5. Large solid mass involving left lower lobe compressing and deviating mediastinum to the right.
cough as did the third patient in our report. No clinical data were available on four patients. All three of the primary pulmonary rhabdomyosarcomas we encountered were found to originate in congenital lung cysts. One was found within a peripheral lung cyst while the other two were discovered within a cystic adenomatoid malformation. The coexistence of two such rare lesions is unlikely to be mere coincidence, especially in three consecutive patients. On review of the 13 previously reported cases, 3 were found in association with congenitally malformed lung. Krous and Sexaue9 described a primary pulmonary rhabdomyosarcoma found within a bronchogenic cyst, while Ueda et al2 and Shariff et al6 documented associated cystic adenomatoid malformations. Myxosarcoma,ll reticulosarcoma,12 and hemangiopericytoma13 have originated in cystic pulmonary lesions. Weinberg et all4 reported the development of a malignant mesenchymoma with a congenital lung cyst 61/2years after it was first recognized. Valderrama et a1,15Martinez et a1,i6and Sumner et all7 reported a
total of 4 cases of pulmonary blastoma that originated in congenital pulmonary cysts. Two theories have been advanced by Lee et all8 to account for the histogenesis of primary pulmonary rhabdomyosarcoma. First of all, malignant transformation of a primitive or uncommitted mesenchymal cell in the stroma could yield a population of cells with a myogenic phenotype. Emergence of clones of myogenie cells then could account for the rhabdomyosarcoma. On the other hand, heterotopic skeletal muscle could be present in the lung. There are several well-documented examples of striated muscle in the lung, primarily in infants at autopsy.1g-21Aterman and Patell described skeletal muscle in an extralobar sequestration. In addition, diffuse striated muscle heteroplasia was observed in a type III cystic adenomatoid malformation in a 365-g stillborn fetus.21 Bolande22 has emphasized the relationship between neoplasm and abnormal morphogenesis, between oncogenesis and teratogenesis. Certain malformations may be “susceptible” to oncogenesis, harboring unstable embryonic mesenchymal cells that may degenerate into a variety of neoplastic cells. Rhabdomyosarcoma is a rare primary tumor of the lung in children which can originate within congenital pulmonary cysts. Spontaneous pneumothorax appears to be a unique clinical manifestation of this lesion. Primary treatment is surgical resection, with adjuvant chemotherapy utilized depending on the stage of clinical disease. The treatment of congenital pulmonary cystic lesions is less clearly defined. It is universally accepted that symptomatic lesions should be resected. This report, along with others mentioned previously, indicates that there is a low but definite risk of malignant degeneration within malformed pulmonary tissue. However, Stocker’sz3 review of 38 cases of cystic adenomatoid malformation at the Armed Forces Institute of Pathology failed to disclose any associated neoplasms. Thus, the frequency and true cause of malignant degeneration remain to be defined. It is evident that careful follow-up is required after identification of malformed pulmonary tissue. Resection should be undertaken for development of symptoms or any change in radiologic appearance. Whether a strategy of resection of all congenital pulmonary malformation is justifiable will require a larger experience. REFERENCES
Fig 6. Primitive rhabdomyomatous elements in cyst wall (see arrow) with complete replacement of the normal covering epithelium. (Original magnification x 100.)
1. Kilman JW, Clatworthy HW, Newton WA, et al: Reasonable surgery for rhabdomyosarcoma. Ann Surg 178:346-351,1973 2. Ueda K, Grupps R, Unger F, et al: Rhabdomyosarcoma of lung arising in congenital cystic adenomatoid malformation. Cancer 40:383-388,1977
RHABDOMYOSARCOMA
IN CONGENITAL
PULMONARY
CYSTS
3. Maurer HM, Moon T, Donaldson M: The Intergroup Rhabdomyosarcoma Study. Cancer 40:2015-20261977 4. Crist WM, Raney RB, Newton W, et al: Intrathoracic soft tissue sarcomas in children. Cancer 50:598-604, 1982 5. Krous HF, Sexauer CL: Embryonal rhabdomyosarcoma arising within a congenital bronchogenic cyst in a child. J Pediatr Surg 16:507-508,198l 6. Shariff S, Thomas JA, Shetty N, et al: Primary pulmonary rhabdomyosarcoma in a child with a review of literature. J Surg Oncol38:26-264,1988 7. Allan BT, Day DD, Dehner LP: Primary pulmonary rhabdomyosarcoma of the lung in children: Report of two cases presenting with spontaneous pneumothorax. Cancer 59:1005-loll,1987 8. Thomas WJ, Koenig HM, Ellwanger FR, et al: Primary pulmonary rhabdomyosarcoma in childhood. Am J Dis Child 1351469-471, 1981 9. Hartmann GE, Shochat SJ: Primary pulmonary neoplasms of childhood: A review. Ann Thorac Surg 36:109-119,1983 10. Fallon G, Schiller M, Kilman JW: Primary rhabdomyosarcoma of the bronchus. Ann Thorac Surg 12:650-654,197l 11. Stephanopoulous C. Catsaras J: Myxosarcoma complicating a cystic hematoma of the lung. Thorax 18:144-145,1963 12. Girard P, Bernard R, Orsini A: Tumeur maligne due poumon developpee aux depens d’un kysti aerien. Arch Fr Pediatr 4~44-47, 1947 13. Babashev BS: Incidence of tumor in the wall of congenital cyst of the lung. Vopr Onkol 18:79-81, 1972
1367
14. Weinberg AG, Currarino G, Moore GC, et al: Mesenchymal neoplasia and congenital pulmonary cysts. Pediatr Radio1 9:179182,198O 15. Valderrama E, Saluja G, Shinde A: Pulmonary blastoma: A report of two cases in children. Am J Surg Pathol2:415-417,1978 16. Martinez JC, Pecero FC, de la Pena CG: Pulmonary blastoma: Report of a case. J Pediatr Surg 13:93-961978 17. Sumner TE, Phelps CR, Crowe JE: Pulmonary blastoma in a child. Am J Roentgen01 133:147-149, 1979 18. Lee SH, Rengachary SS, Paramesh J: Primary pulmonary rhabdomyosarcoma. A case report and review of the literature. Hum Pathol 12:92-96.1981 19. Aterman K, Pate1 S: Striated muscle in the lung. Am J Anat 128:341-358.1970 20. Remberger K. Hubnu G: Rhabdomyomatous dysplasia of the lung. Virchows Arch Pathol Anat 363:363-369, 1974 21. Chi JG, Shong YK: Diffuse striated muscle heretoplasia of the lung: An autopsy study. Arch Pathol Lab Med 106:641-644, 1982 22. Bolande RP: Teratogenesis and oncogenesis, in Wilson JG, Fraser FC (eds): Handbook of Teratology, vol 2. New York, NY, Plenum, 1974, pp 288-306 23. Stocker JT, Madewell JE, Drake RM: Cystic adenomatoid malformation of the lung-Classification and morphologic spectrum. Hum Path01 8:155-171. 1977
Arising Within Congenital Report of Three Cases
G.K. Blair, G.C. Fraser, P.G. Ashmore,
Pulmonary
Cysts:
J.G. LeBlanc, S.S. Sett, P. Rogers, J.F. Magee, G.P. Taylor,
and J. Dimmick Vancouver,
British
Columbia
l Over the past 9 months, three cases of primary pulmonary rhabdomyosarcoma
have been treated at British Colum-
bia Children’s Hospital. Two patients (aged 24 and 37 months) presented with spontaneous
pneumothoraces
and had cystic
changes in the affected lung on chest radiograph. patient
(aged 42 months) was evaluated
The third
for chronic cough,
fever, and failure to thrive. Chest x-ray showed a large mass in the left lower lobe as well as mediastinal
adenopathy.
All
three of these lesions originated within congenital lung cysts, one a peripheral adenomatoid
bronchogenic
malformations.
is a significant
risk for the development
coma within malformed Copyright
cyst and the others
cystic
This report suggests that there of rhabdomyosar-
pulmonary tissue.
o 1992 by W.B. Saunders Company
INDEX WORDS:
Rhabdomyosarcoma,
pulmonary;
lung cyst,
congenital.
A
LTHOUGH rhabdomyosarcoma is an uncommon childhood malignancy, it is the most frequently encountered soft tissue sarcoma found in infants and children.’ The head and neck, extremities, genitourinary tract, and trunk are the most common primary sites, with metastatic lesions usually found in the lungs. Primary intrathoracic rhabdomyosarcomas are rare, and there have only been 13 reported cases of primary pulmonary lesions.‘-lo Although the majority of these have been endobronchial, several reports have documented the origin of the rhabdomyosarcoma within congenital pulmonary cystic lesions.1+5,6 In this report we describe three cases of primary pulmonary rhabdomyosarcoma that were encountered at this institution over the past 9 months. TWO of these neoplasms were found within cystic adenomatoid malformations, whereas the third originated within a peripheral bronchogenic cyst.
From the Divisions of Pediaftic General Surgery, Cardiothoracic Surgery, Oncology and Pathofogy, British Coiumbia Children’s Hospital, Vancouver, British Columbia. Presented at the 23rd Annual Meeting of the Canadian Association of Paediattic Surgeons, Quebec City, Quebec, September 19-22, 1991. Address reprint requests to James J. Murphy, MD, Section of Surgery-Room IL7 British Columbia Children’s Hospital, 4480 Oak St, Vancouver, BC V6H 3V4_ Canada. Copyright o 1992 by W B. Saunders Company 0022-3468192/2710-0031$03.00/O
1364
CASE REPORTS Case 1 A 2-year-old girl was in her usual state of good health until the day of hospital admission when she developed the acute onset of shortness of breath, tachypnea, and tachycardia. Chest radiograph showed a tension pneumothorax on the right. Chest tube was placed. Repeat chest x-ray demonstrated partial reexpansion of the lung as well as cystic changes at the right lung base. She was plagued by recurrent pneumothoraces requiring repeated chest tube placement. Computed tomography (CT) scan showed cystic lesions in the right lower lobe. The mediastinum and pleura were normal. Right thoracotomy and wedge resection of a cystic lesion involving right lower lobe was performed. Pathology report described a 7 x 5 x 2 cm multiloculated lesion. Embryonal rhabdomyosarcoma was found within a developmental (peripheral bronchogenic) cyst (Fig 1). The cyst itself appeared to be an outgrowth of a small focus of dysplastic lung. The tumor microscopically involved the pleura, although the proximal margin was clear. The patient made an uneventful recovery and was discharged on postoperative day 3. Metastatic workup was negative. Extent of disease was deemed to be stage II with microscopic residual disease in the pleural cavity. She was randomized to regimen 33 of the IRS-3 group 2 study. Chemotherapeutic protocol included Actinomycin D, Vincristine, and Adriamycin for 1 year. She did not receive radiation therapy. At 1 year postresection she has shown no evidence of recurrent or residual disease on follow-up CT scan.
Case
2
A 3-year-old girl was well until 3 weeks prior to admission when she developed a flu-like illness. On the day of admission she complained of the acute onset of cough, shortness of breath, and right-sided chest discomfort. Chest x-ray demonstrated a right tension pneumothorax (Fig 2). Chest tube was placed but air leak persisted for several days. CT scan showed cystic and solid nodular lesions involving the right middle and lower lobes (Fig 3). She subsequently underwent right middle and lower lobectomy. Pathology reports describe a 3.0 x 5.5 x 2.3 cm lesion with solid and large cystic components in the lower lobe. The middle lobe was involved to a lesser extent with a similar process. Embryonal rhabdomyosarcoma was found within a cystic adenomatoid malformation in botyroid fashion (Fig 4). Most of the cyst wall as well as the polypoid lesions within the cyst itself contained rhabdomyosarcoma. Embryonal rhabdomyosarcoma was present at the pleural surface of the cyst in a few areas, including the point of rupture of
the dominant cyst. Her postoperative
course was complicated by recurrent pneumothoraces and persistent air leak which eventually resolved. Although she technically had stage II disease with microscopic residual, she was treated with the group III IRS CCG71 regimen C. This includes Vincristine, Ifofamide, and VP-16 every 3 weeks for 1 year. She did not receive adjuvant radiation therapy. Recent evaluation 3 months after resection has not identified any residual or recurrent disease.
JournalofPediatricSurgery,
Vol27, No 10 (October), 1992: pp 1364-1367
RHABDOMYOSARCOMA
IN CONGENITAL
PULMONARY CYSTS
Fig 1. Intact cuboidal and columnar pseudostratified epithelium of cyst lining (see arrows) with rhabdomyosarcoma adjacent to it. (Original magnification x40.)
Case 3 A 3’/z-year-old boy presented with a several-month history of failure to thrive, lethargy, fever, cough, and iron deficiency anemia. Chest radiograph demonstrated a large mass involving the left lower lobe. The mass was compressing the mediastinum and deviating it to the right. CT scan confirmed the presence of this mass and also showed hilar adenopathy (Fig 5). Left thoracotomy was performed with resection of the left lower lobe. Hilar and intralobar lymph nodes were involved. Pathology demonstrated a 10 x 10 x 9 cm vascular soft tissue mass. The histology showed a rhabdomyosarcoma originating within a cystic adenomatoid malformation. There was complete replacement of the cyst wall with primitive rhabdomyomatous elements (Fig 6). Tumor penetrated viscera1 pleura and hilar lymph nodes contained metastatic tumor. He made an uneventful recovery from surgery. Clinically his extent of disease was stage IIB with nodal disease. He was started on the group II IRS protocol receiving Vincristine every 3 weeks
Fig 2.
Right tension pneumothorax
due to cyst rupture.
Fig 3. Cystic and solid components of rhabdomyosarcoma ing right middle and lower lobes.
involv-
for 1 year. Recent evaluation 6 months postresection has failed to identify residual or recurrent disease. DISCUSSION
Despite the well-documented fact that primary pulmonary rhabdomyosarcoma is an extremely rare lesion, we have evaluated and treated three cases over the past 9 months. To date, only 13 cases of this neoplasm have been reported in the pediatric age group.l-lo Only 3 of the 646 children registered with the Intergroup Rhabdomyosarcoma Study had primary pulmonary lesions.3 Allan et al7 and Hartmann et al9 both documented two cases, while the others were all single case reports. Two of the three patients were essentially asymptomatic until development of spontaneous tension pneumothorax. In reviewing the previous reports, 22% (2/9) of the children presented with a similar picture, while 67% (6/9) complained of fever and
Fig 4. Lung cyst with botyroid invasion of rhabdomyosarcoma. Mucosal lining of cyst (see arrow) with rhabdomyablasts impinging on it and beginning invasion. (Original magnification x 100.)
MURPHY ET AL
1366
Fig 5. Large solid mass involving left lower lobe compressing and deviating mediastinum to the right.
cough as did the third patient in our report. No clinical data were available on four patients. All three of the primary pulmonary rhabdomyosarcomas we encountered were found to originate in congenital lung cysts. One was found within a peripheral lung cyst while the other two were discovered within a cystic adenomatoid malformation. The coexistence of two such rare lesions is unlikely to be mere coincidence, especially in three consecutive patients. On review of the 13 previously reported cases, 3 were found in association with congenitally malformed lung. Krous and Sexaue9 described a primary pulmonary rhabdomyosarcoma found within a bronchogenic cyst, while Ueda et al2 and Shariff et al6 documented associated cystic adenomatoid malformations. Myxosarcoma,ll reticulosarcoma,12 and hemangiopericytoma13 have originated in cystic pulmonary lesions. Weinberg et all4 reported the development of a malignant mesenchymoma with a congenital lung cyst 61/2years after it was first recognized. Valderrama et a1,15Martinez et a1,i6and Sumner et all7 reported a
total of 4 cases of pulmonary blastoma that originated in congenital pulmonary cysts. Two theories have been advanced by Lee et all8 to account for the histogenesis of primary pulmonary rhabdomyosarcoma. First of all, malignant transformation of a primitive or uncommitted mesenchymal cell in the stroma could yield a population of cells with a myogenic phenotype. Emergence of clones of myogenie cells then could account for the rhabdomyosarcoma. On the other hand, heterotopic skeletal muscle could be present in the lung. There are several well-documented examples of striated muscle in the lung, primarily in infants at autopsy.1g-21Aterman and Patell described skeletal muscle in an extralobar sequestration. In addition, diffuse striated muscle heteroplasia was observed in a type III cystic adenomatoid malformation in a 365-g stillborn fetus.21 Bolande22 has emphasized the relationship between neoplasm and abnormal morphogenesis, between oncogenesis and teratogenesis. Certain malformations may be “susceptible” to oncogenesis, harboring unstable embryonic mesenchymal cells that may degenerate into a variety of neoplastic cells. Rhabdomyosarcoma is a rare primary tumor of the lung in children which can originate within congenital pulmonary cysts. Spontaneous pneumothorax appears to be a unique clinical manifestation of this lesion. Primary treatment is surgical resection, with adjuvant chemotherapy utilized depending on the stage of clinical disease. The treatment of congenital pulmonary cystic lesions is less clearly defined. It is universally accepted that symptomatic lesions should be resected. This report, along with others mentioned previously, indicates that there is a low but definite risk of malignant degeneration within malformed pulmonary tissue. However, Stocker’sz3 review of 38 cases of cystic adenomatoid malformation at the Armed Forces Institute of Pathology failed to disclose any associated neoplasms. Thus, the frequency and true cause of malignant degeneration remain to be defined. It is evident that careful follow-up is required after identification of malformed pulmonary tissue. Resection should be undertaken for development of symptoms or any change in radiologic appearance. Whether a strategy of resection of all congenital pulmonary malformation is justifiable will require a larger experience. REFERENCES
Fig 6. Primitive rhabdomyomatous elements in cyst wall (see arrow) with complete replacement of the normal covering epithelium. (Original magnification x 100.)
1. Kilman JW, Clatworthy HW, Newton WA, et al: Reasonable surgery for rhabdomyosarcoma. Ann Surg 178:346-351,1973 2. Ueda K, Grupps R, Unger F, et al: Rhabdomyosarcoma of lung arising in congenital cystic adenomatoid malformation. Cancer 40:383-388,1977
RHABDOMYOSARCOMA
IN CONGENITAL
PULMONARY
CYSTS
3. Maurer HM, Moon T, Donaldson M: The Intergroup Rhabdomyosarcoma Study. Cancer 40:2015-20261977 4. Crist WM, Raney RB, Newton W, et al: Intrathoracic soft tissue sarcomas in children. Cancer 50:598-604, 1982 5. Krous HF, Sexauer CL: Embryonal rhabdomyosarcoma arising within a congenital bronchogenic cyst in a child. J Pediatr Surg 16:507-508,198l 6. Shariff S, Thomas JA, Shetty N, et al: Primary pulmonary rhabdomyosarcoma in a child with a review of literature. J Surg Oncol38:26-264,1988 7. Allan BT, Day DD, Dehner LP: Primary pulmonary rhabdomyosarcoma of the lung in children: Report of two cases presenting with spontaneous pneumothorax. Cancer 59:1005-loll,1987 8. Thomas WJ, Koenig HM, Ellwanger FR, et al: Primary pulmonary rhabdomyosarcoma in childhood. Am J Dis Child 1351469-471, 1981 9. Hartmann GE, Shochat SJ: Primary pulmonary neoplasms of childhood: A review. Ann Thorac Surg 36:109-119,1983 10. Fallon G, Schiller M, Kilman JW: Primary rhabdomyosarcoma of the bronchus. Ann Thorac Surg 12:650-654,197l 11. Stephanopoulous C. Catsaras J: Myxosarcoma complicating a cystic hematoma of the lung. Thorax 18:144-145,1963 12. Girard P, Bernard R, Orsini A: Tumeur maligne due poumon developpee aux depens d’un kysti aerien. Arch Fr Pediatr 4~44-47, 1947 13. Babashev BS: Incidence of tumor in the wall of congenital cyst of the lung. Vopr Onkol 18:79-81, 1972
1367
14. Weinberg AG, Currarino G, Moore GC, et al: Mesenchymal neoplasia and congenital pulmonary cysts. Pediatr Radio1 9:179182,198O 15. Valderrama E, Saluja G, Shinde A: Pulmonary blastoma: A report of two cases in children. Am J Surg Pathol2:415-417,1978 16. Martinez JC, Pecero FC, de la Pena CG: Pulmonary blastoma: Report of a case. J Pediatr Surg 13:93-961978 17. Sumner TE, Phelps CR, Crowe JE: Pulmonary blastoma in a child. Am J Roentgen01 133:147-149, 1979 18. Lee SH, Rengachary SS, Paramesh J: Primary pulmonary rhabdomyosarcoma. A case report and review of the literature. Hum Pathol 12:92-96.1981 19. Aterman K, Pate1 S: Striated muscle in the lung. Am J Anat 128:341-358.1970 20. Remberger K. Hubnu G: Rhabdomyomatous dysplasia of the lung. Virchows Arch Pathol Anat 363:363-369, 1974 21. Chi JG, Shong YK: Diffuse striated muscle heretoplasia of the lung: An autopsy study. Arch Pathol Lab Med 106:641-644, 1982 22. Bolande RP: Teratogenesis and oncogenesis, in Wilson JG, Fraser FC (eds): Handbook of Teratology, vol 2. New York, NY, Plenum, 1974, pp 288-306 23. Stocker JT, Madewell JE, Drake RM: Cystic adenomatoid malformation of the lung-Classification and morphologic spectrum. Hum Path01 8:155-171. 1977
