Eur J Pediatr (1992) 151 : 488-491
European Journal of
Pediatrics
9 Springer-Verlag 1992
The hepatic malignant mesenchymoma: a case report M. C. Tozzi I, L. Tarani I, R. DiNardo 2, L. Bruni I, C. Cappelli I, G. Funaro I, F. Cozzi 3, and P. Vignetti I 1Fifth Paediatric Department, 2Second Radiology Department, 3paediatric Surgery Department, University of Rome, 5a Cattedra di Clinica Pediatrica, Policlinico Umberto I, v. le Regina Elena 324, 1-00161, Roma, Italy Received April 16, 1991 / Accepted after revision December 11, 1991
Abstract. We report a case of hepatic m e s e n c h y m o m a in an 8-year-old girl who presented with abdominal pain and ultrasonographic diagnosis of hepatic echinococcosis. Due to the good general condition of the patient and the diagnostic confirmation of liver hydatid disease by the CT scan, antiparasitic therapy with albendazole was started. After 1 month of therapy the girl's general condition worsened as did the ultrasonographic picture. On laparatomy a large cystic mass was observed within the right hepatic lobe and was removed. Pathological examination of the mass excluded an echinococcal cyst and demonstrated a malignant hepatic mesenchymoma. Key words: Cyst - Liver - M e s e n c h y m o m a
Introduction Malignant m e s e n c h y m o m a of the liver is of considerable paediatric interest. It is somewhat rare (5% of all primary hepatic tumours in children) and presents with vague and unspecific symptoms which can m a k e it difficult to identify [12, 13, 19]. The tumour occurs prevalently between 5 and 10 years of age with the following symptoms: abdominal pain, fever, anorexia, weight loss, vomiting and the appearance of an abdominal mass in the epigastrium or in the right superior quadrant. The haematochemical investigations are not very indicative, while instrumental investigation, such as US scan, arteriography or CT scan, only supply details concerning the size and the structure (solid or cystic) of the mass and its relationship with the surrounding organs [4, 16]. It is therefore necessary to proceed surgically as soon as possible in order to reveal a rather voluminous mass, often of cystic appearance, limited to one hepatic lobe. The exact diagnosis can only be formulated on the basis of a histological examination. The prognosis is generally p o o r [14, 16].
Offprints requests to: M. C. Tozzi
Case report The patient presented when she was 8 years old. The child had been admitted to another hospital 10 days earlier for pain in the right hypocondrium, with no other symptoms. An abdominal US scan revealed a large cystic mass of inhomogeneous content in the right lobe of the liver. Hepatic echinococcosis was diagnosed and the patient was transferred to our Institute.
Family history Paternal grandfather died at 61 years of age from brain tumour; paternal grandmother underwent hysterectomy for uterine carcinoma; 40-year old-mother currently undergoing treatment for mammary carcinoma; maternal uncle affected by hydatid cyst of the liver.
Physical examination Good general condition; weight 23.6kg (25th-50th percentile); height 134 cm (90th percentile). Abdomen palpable without pain; inferior margin of liver 2 cm from costal margin; spleen not palpable.
Fig. 1. CT scan. Multilocular, low-density tumefaction, with regular, clean-cut borders after injection of contrast medium
489
Fig. 2. US scan. Longitudinal scan carried out with real-time sector. Voluminous formation in the superior half of the right hepatic lobe, with mixed echostructure, prevalently echodense, with sonolucent areas (F, normal hepatic parenchyma; arrows, diaphragm)
Laboratory analyses Routine tests were normal with the exception of the ESR (40) and serum GOT (461U) and GPT (401U). Casoni intracutaneous test was negative. Abdominal and pelvic CT scan (Fig. 1): "gross multilocular cystic formation (52 • 79 • 70 mm), of low density with attenuation values unchanged after injection of contrast medium; bile ducts of normal calibre; probable parasitic nature. No focal lesion of the spleen, adrenal glands, kidneys or pelvis." A probable parasitic disease was diagnosed and treatment with albendazole (400 mg/day) initiated until availability of the results of specific tests for echinococcosis (indirect haemagglutination, lymphocyte blast formation and basophil degranulation stimulated by the liquid content of the cyst, histamine release test). After 1 month treatment another hepatic US scan was carried out, due to worsening of the patient's condition (anorexia, fever, abdominal pain) and to the negative outcome of the specific serological tests. The scan (Fig. 2) revealed "a mass of 12.6 x 9.7 cm, of inhomogeneous echostructure (complex mass), with a regular outline and clean-cut borders, and compression on blood vessels and surrounding tissues, without infiltration. No alterations were revealed within the remaining liver parenchyma; abundant corpusculated ascitic fluid was present which gave rise to a suspicion of "haemoperitoneum". Carcinoembryonic antigen and plasma afetoprotein levels were normal. The increase in size of the cyst and, above all, the presence of corpusculated ascitic fluid in the pelvic cavity suggested the presence of a cyst of tumonral origin, rather than of parasitic genesis; this was also supported by the negative specific echinococcus serological tests. Surgery was therefore performed, the tumour was removed by means of an atypical hepatic resection, cleaving the pseudocapsule of the tumour and the surrounding hepatic tissue (tumourectomy). Histological examination of the removed mass showed a basically cystic structure (Figs. 3, 4). The septa separating the cavities contained: myxoid tissue, aggregates of hepatocytes (Fig. 5), biliary-type ductules with variably ectasic lumina and groups of anaplastic cells, many of which had bizarre, monstrous nuclei (Fig. 6). Immunohistolochemical analyses for u-feto-protein and myoglobin were negative, while that for ct-l-antitrypsin was positive. A diagnosis of malignant mesenchymoma was thus made. The patient was then admitted to a Paediatric Oncology Centre where she underwent chemotherapy with cisplatin and adryamicin.
Fig. 3. Small enlargement of the neoplasm, showing a typically cystic appearence. Haematoxylin-eosin, 40 x Fig. 4. Cystic wall lined by cylindrical, biliary-like, mature and typical epithelium. Haematoxylin-eosin, 350 •
The child is in good health 2.5 years after the operation and has not shown signs of tumour recurrence or metastasis.
Discussion M a l i g n a n t m e s e n c h y m o m a of the liver was first d e s c r i b e d b y S t o u t in 1948 [17] b u t it was n o t until 1978 t h a t S t o c k e r a n d I s h a k [16] d e f i n e d t h e h i s t o p a t h o l o g i c a l crit e r i a n e c e s s a r y for a m o r e p r e c i s e i d e n t i f i c a t i o n of this t u m o u r a c h i e v e d b y r e v i e w i n g the a v a i l a b l e l i t e r a t u r e a n d a n a l y s i n g 31 cases w h i c h c a m e f r o m t h e A r m e d F o r c e s I n s t i t u t e o f P a t h o l o g y ( W a s h i n g t o n , U S A ) . This n e o p l a s m has also b e e n r e f e r r e d to b y a v a r i e t y o f t e r m s such as f i b r o m y x o s a r c o m a , u n d i f f e r e n t i a t e d e m b r y o n a l s a r c o m a , e m b r y o n a l s a r c o m a o r simply m e s e n c h y m o m a . A t p r e s e n t , h o w e v e r , in a g r e e m e n t with S t o c k e r ' s definition, t h e t e r m u n d i f f e r e n t i a t e d ( e m b r y o n a l ) s a r c o m a is preferred. Under these various terms we have compiled a b o u t 140 cases b y e x a m i n i n g reviews a n d single case rep o r t s [1, 2, 5, 7, 8, 12, 16, 20]. I n a g r e e m e n t with t h e m a j o r i t y of a u t h o r s , t h e des c r i p t i o n of o u r case c o n f i r m s t h a t a p o s i t i v e diagnosis o f m a l i g n a n t h e p a t i c m e s e n c h y m o m a is o n l y p o s s i b l e b y carrying out a histological examination.
490 that is the cylindrical epithelium delimiting the cysts and the epithelial clusters in the intercystic septa, was represented by biliary-like epithelium and well differentiated, mature and typical hepatocytes, respectively, contrary to what is observed in hepatoblastoma. On the other hand the mesenchymal c o m p o n e n t presented an undeniably anaplastic appearance; in fact, within the loose connective tissue of mixoid appearance, there were large cells with hyperchromatic, bizarre anaplastic nuclei. The observation that anaplasia only involved the mesenchymal tissue led to the diagnosis of malignant m e s e n c h y m o m a or embryonic sarcoma of the liver. The prognosis of this type of neoplasm is usually p o o r and the death-rate at this time is about 86% [7]. A survival period of over 3 years is considered possible in 35% of all cases [8], when surgical resection of the liver is followed by adequate c h e m o t h e r a p y (cisplatin, adriamycin, vincristine, cyclophosphamide, actinomycin D and others) [11, 12, 14, 15, 18]. On the other hand, some authors maintain that long-term survival is also possible with surgery alone and that chemotherapeutic treatment should only be applied under certain circumstances [10]. In our case both surgery and c h e m o t h e r a p y have shown to be valid and the patient, 2.5 years after the operation, is in good general condition and has not shown clinical or radiological signs of localized recurrence or metastasis. Fig. 5. Cell cluster within an intercystic septum containing mature and typical hepatocytes. Haematoxylin-eosin, 350 •
Acknowledgement. Many thanks to Prof. Alberto Ceccamea for the histopathology text and help in preparing the figures.
Fig. 6. Intercystic septum. Large cells with hyperchromatic bizarre nuclei are contained within the loose connective tissue of myxoid appearence
References
In fact this tumour presents such vague and non-specific symptoms that clinical diagnosis is extremely difficult, if not impossible. In our case the initial hypothesis of echinococcal cyst of the liver was based on a few clinical signs such as pain in the hepatic area and modest hepatomegaly in a patient with no other s y m p t o m and in good general condition. The results of the US and CT scans seemed to be in agreement with this hypothesis, thus the initial treatment with albendazole seemed justified. The rapid worsening of the child's general condition, the negative result of the blood tests and the following US scan indicated a pathology of the liver of nonparasitic origin [6, 9]. Also in view of the age and the symptoms of the child, a different diagnostic hypothesis could be m a d e considering other tumoural formations of the liver, such as: mesenchymal h a m a r t o m a , malignant mesenchymoma with a cystic component and cystic hepatoblastoma [3]. Histological examination of the excised mass demonstrated the existence of a malignant neoplasm which was characterized by a double cystic component, both epithelial and mesenchymal. The diagnostic hypothesis of a mixed hepatoblastoma was made, due to the presence of both types of tissue and considering the fact that this tum o u r is the most frequent malignant neoplasm of the liver in childhood. However, the epithelial component,
1. Cimarelli S, Virgilio A, Giovanuelli A (1987) Sarcoma primitivo embrionale del fegato. Presentazione di un caso. Minerva Chir 42 : 1427-1430 2. Cozzutto C, DeBernardi B, Comelli A (1981) Malignant mesenchymoma of the liver in children: a clinicopathological and ultrastructural study. Hum Pathol 12 : 481-485 3. De Maioribus AC, Lally PK, Sim K, Isaacs H, Mahour H (1990) Mesenchymal hamartoma of the liver. A 35-year review. Arch Surg 125:598-600 4. Federici S, Cuoghi D, Ceccarelli PL (1988) Structural analogies and differential diagnosis between benign and malignant mesenchymal neoplasms of the liver in childhood. Ital J Pediatr Surg Sci 2:11-15 5. Finegold M (1986) Pathology of neoplasia in children and adolescents. In: Bennington JL (ed) Major problems in pathology. W. B. Saunders, Philadelphia, vol 18, pp 360-363 6. Gurses H, Sungur R, Orkan K (1987) Ultrasound diagnosis of liver hydatid disease, Acta Radiol 28:161-163 7. Lack EE, Schloo BL, Azumi N (1991) Undifferentiated (embryonal) sarcoma of the liver. Clinical and pathologic study of 16 cases with emphasis on immunohistochemical features. Am J Surg Pathol 15 : 1-16 8. Leuschner I, Schmid D, Harms D (1990) Undifferentiated sarcoma of the liver in childhood: morphology, flow cytometry and literature review. Hum Pathol 21 : 68-76 9. Lewall D, Mc Corkell SJ (1985) Hepatic echinococcal cysts: sonographic appearance and classification. Radiology 155 : 773775 10. Marshall DG (1990) Malignant mesenchymoma of the liver in children. Letter comment. J Pediatr Surg 25 : 583 11. Newman KD, Schisgall R, Reaman G, Guzzetta PG (1989) Malignant mesenchymoma of the liver in children. J Pediatr Surg 24 : 781-783
491 12. Perilongo G, Carli M, Sainati L (1987) Undifferentiated (embryonal) sarcoma of the liver in childhood: results of a retrospective Italian study. Tumori 73 : 213-217 13. Randolph JG, Guzzetta PC (1986) Tumors of the liver. In: Welch KJ, et al (eds) Pediatric surgery. Year Book Medical Publisher, Chicago, pp 302-310 14. Smithson WA, Telander RL, Carney JA (1982) Mesenchymoma of the liver in childhood: five-year survival after combined-modality treatment. J Pediatr Surg 17 : 70-72 15. Steiner M, Bostrum B, Leonard AS (1989) Undifferentiated (embryonal) sarcoma of the liver. A clinicopathologic study of a survivor treated with combined technique therapy. Cancer 64:1318-1322
16. Stocker JT, Ishak KG (1978) Undifferentiated (embryonal) sarcoma of the liver. Report of 31 cases. Cancer 42:336-348 17. Stout AP (1948) Mesenchymoma, the mixed tumor of mesenchymal derivatives. Ann Surg 127 : 278-290 18. Ware R, Friedman HS, Filston HC, et al (1988) Childhood hepatic mesenchymoma: successful treatment with surgery and multiple-agent chemotherapy. Med Pediatr Oncol 16: 62-65 19. Weinberg AG, Finegold MJ (1983) Primary hepatic tumors of childhood. Hum Pathol 14 : 512-537 20. Case records of Massachusetts General Hospital. Case 19. (1990) N Engl J Med 322 : 213-217
European Journal of
Pediatrics
9 Springer-Verlag 1992
The hepatic malignant mesenchymoma: a case report M. C. Tozzi I, L. Tarani I, R. DiNardo 2, L. Bruni I, C. Cappelli I, G. Funaro I, F. Cozzi 3, and P. Vignetti I 1Fifth Paediatric Department, 2Second Radiology Department, 3paediatric Surgery Department, University of Rome, 5a Cattedra di Clinica Pediatrica, Policlinico Umberto I, v. le Regina Elena 324, 1-00161, Roma, Italy Received April 16, 1991 / Accepted after revision December 11, 1991
Abstract. We report a case of hepatic m e s e n c h y m o m a in an 8-year-old girl who presented with abdominal pain and ultrasonographic diagnosis of hepatic echinococcosis. Due to the good general condition of the patient and the diagnostic confirmation of liver hydatid disease by the CT scan, antiparasitic therapy with albendazole was started. After 1 month of therapy the girl's general condition worsened as did the ultrasonographic picture. On laparatomy a large cystic mass was observed within the right hepatic lobe and was removed. Pathological examination of the mass excluded an echinococcal cyst and demonstrated a malignant hepatic mesenchymoma. Key words: Cyst - Liver - M e s e n c h y m o m a
Introduction Malignant m e s e n c h y m o m a of the liver is of considerable paediatric interest. It is somewhat rare (5% of all primary hepatic tumours in children) and presents with vague and unspecific symptoms which can m a k e it difficult to identify [12, 13, 19]. The tumour occurs prevalently between 5 and 10 years of age with the following symptoms: abdominal pain, fever, anorexia, weight loss, vomiting and the appearance of an abdominal mass in the epigastrium or in the right superior quadrant. The haematochemical investigations are not very indicative, while instrumental investigation, such as US scan, arteriography or CT scan, only supply details concerning the size and the structure (solid or cystic) of the mass and its relationship with the surrounding organs [4, 16]. It is therefore necessary to proceed surgically as soon as possible in order to reveal a rather voluminous mass, often of cystic appearance, limited to one hepatic lobe. The exact diagnosis can only be formulated on the basis of a histological examination. The prognosis is generally p o o r [14, 16].
Offprints requests to: M. C. Tozzi
Case report The patient presented when she was 8 years old. The child had been admitted to another hospital 10 days earlier for pain in the right hypocondrium, with no other symptoms. An abdominal US scan revealed a large cystic mass of inhomogeneous content in the right lobe of the liver. Hepatic echinococcosis was diagnosed and the patient was transferred to our Institute.
Family history Paternal grandfather died at 61 years of age from brain tumour; paternal grandmother underwent hysterectomy for uterine carcinoma; 40-year old-mother currently undergoing treatment for mammary carcinoma; maternal uncle affected by hydatid cyst of the liver.
Physical examination Good general condition; weight 23.6kg (25th-50th percentile); height 134 cm (90th percentile). Abdomen palpable without pain; inferior margin of liver 2 cm from costal margin; spleen not palpable.
Fig. 1. CT scan. Multilocular, low-density tumefaction, with regular, clean-cut borders after injection of contrast medium
489
Fig. 2. US scan. Longitudinal scan carried out with real-time sector. Voluminous formation in the superior half of the right hepatic lobe, with mixed echostructure, prevalently echodense, with sonolucent areas (F, normal hepatic parenchyma; arrows, diaphragm)
Laboratory analyses Routine tests were normal with the exception of the ESR (40) and serum GOT (461U) and GPT (401U). Casoni intracutaneous test was negative. Abdominal and pelvic CT scan (Fig. 1): "gross multilocular cystic formation (52 • 79 • 70 mm), of low density with attenuation values unchanged after injection of contrast medium; bile ducts of normal calibre; probable parasitic nature. No focal lesion of the spleen, adrenal glands, kidneys or pelvis." A probable parasitic disease was diagnosed and treatment with albendazole (400 mg/day) initiated until availability of the results of specific tests for echinococcosis (indirect haemagglutination, lymphocyte blast formation and basophil degranulation stimulated by the liquid content of the cyst, histamine release test). After 1 month treatment another hepatic US scan was carried out, due to worsening of the patient's condition (anorexia, fever, abdominal pain) and to the negative outcome of the specific serological tests. The scan (Fig. 2) revealed "a mass of 12.6 x 9.7 cm, of inhomogeneous echostructure (complex mass), with a regular outline and clean-cut borders, and compression on blood vessels and surrounding tissues, without infiltration. No alterations were revealed within the remaining liver parenchyma; abundant corpusculated ascitic fluid was present which gave rise to a suspicion of "haemoperitoneum". Carcinoembryonic antigen and plasma afetoprotein levels were normal. The increase in size of the cyst and, above all, the presence of corpusculated ascitic fluid in the pelvic cavity suggested the presence of a cyst of tumonral origin, rather than of parasitic genesis; this was also supported by the negative specific echinococcus serological tests. Surgery was therefore performed, the tumour was removed by means of an atypical hepatic resection, cleaving the pseudocapsule of the tumour and the surrounding hepatic tissue (tumourectomy). Histological examination of the removed mass showed a basically cystic structure (Figs. 3, 4). The septa separating the cavities contained: myxoid tissue, aggregates of hepatocytes (Fig. 5), biliary-type ductules with variably ectasic lumina and groups of anaplastic cells, many of which had bizarre, monstrous nuclei (Fig. 6). Immunohistolochemical analyses for u-feto-protein and myoglobin were negative, while that for ct-l-antitrypsin was positive. A diagnosis of malignant mesenchymoma was thus made. The patient was then admitted to a Paediatric Oncology Centre where she underwent chemotherapy with cisplatin and adryamicin.
Fig. 3. Small enlargement of the neoplasm, showing a typically cystic appearence. Haematoxylin-eosin, 40 x Fig. 4. Cystic wall lined by cylindrical, biliary-like, mature and typical epithelium. Haematoxylin-eosin, 350 •
The child is in good health 2.5 years after the operation and has not shown signs of tumour recurrence or metastasis.
Discussion M a l i g n a n t m e s e n c h y m o m a of the liver was first d e s c r i b e d b y S t o u t in 1948 [17] b u t it was n o t until 1978 t h a t S t o c k e r a n d I s h a k [16] d e f i n e d t h e h i s t o p a t h o l o g i c a l crit e r i a n e c e s s a r y for a m o r e p r e c i s e i d e n t i f i c a t i o n of this t u m o u r a c h i e v e d b y r e v i e w i n g the a v a i l a b l e l i t e r a t u r e a n d a n a l y s i n g 31 cases w h i c h c a m e f r o m t h e A r m e d F o r c e s I n s t i t u t e o f P a t h o l o g y ( W a s h i n g t o n , U S A ) . This n e o p l a s m has also b e e n r e f e r r e d to b y a v a r i e t y o f t e r m s such as f i b r o m y x o s a r c o m a , u n d i f f e r e n t i a t e d e m b r y o n a l s a r c o m a , e m b r y o n a l s a r c o m a o r simply m e s e n c h y m o m a . A t p r e s e n t , h o w e v e r , in a g r e e m e n t with S t o c k e r ' s definition, t h e t e r m u n d i f f e r e n t i a t e d ( e m b r y o n a l ) s a r c o m a is preferred. Under these various terms we have compiled a b o u t 140 cases b y e x a m i n i n g reviews a n d single case rep o r t s [1, 2, 5, 7, 8, 12, 16, 20]. I n a g r e e m e n t with t h e m a j o r i t y of a u t h o r s , t h e des c r i p t i o n of o u r case c o n f i r m s t h a t a p o s i t i v e diagnosis o f m a l i g n a n t h e p a t i c m e s e n c h y m o m a is o n l y p o s s i b l e b y carrying out a histological examination.
490 that is the cylindrical epithelium delimiting the cysts and the epithelial clusters in the intercystic septa, was represented by biliary-like epithelium and well differentiated, mature and typical hepatocytes, respectively, contrary to what is observed in hepatoblastoma. On the other hand the mesenchymal c o m p o n e n t presented an undeniably anaplastic appearance; in fact, within the loose connective tissue of mixoid appearance, there were large cells with hyperchromatic, bizarre anaplastic nuclei. The observation that anaplasia only involved the mesenchymal tissue led to the diagnosis of malignant m e s e n c h y m o m a or embryonic sarcoma of the liver. The prognosis of this type of neoplasm is usually p o o r and the death-rate at this time is about 86% [7]. A survival period of over 3 years is considered possible in 35% of all cases [8], when surgical resection of the liver is followed by adequate c h e m o t h e r a p y (cisplatin, adriamycin, vincristine, cyclophosphamide, actinomycin D and others) [11, 12, 14, 15, 18]. On the other hand, some authors maintain that long-term survival is also possible with surgery alone and that chemotherapeutic treatment should only be applied under certain circumstances [10]. In our case both surgery and c h e m o t h e r a p y have shown to be valid and the patient, 2.5 years after the operation, is in good general condition and has not shown clinical or radiological signs of localized recurrence or metastasis. Fig. 5. Cell cluster within an intercystic septum containing mature and typical hepatocytes. Haematoxylin-eosin, 350 •
Acknowledgement. Many thanks to Prof. Alberto Ceccamea for the histopathology text and help in preparing the figures.
Fig. 6. Intercystic septum. Large cells with hyperchromatic bizarre nuclei are contained within the loose connective tissue of myxoid appearence
References
In fact this tumour presents such vague and non-specific symptoms that clinical diagnosis is extremely difficult, if not impossible. In our case the initial hypothesis of echinococcal cyst of the liver was based on a few clinical signs such as pain in the hepatic area and modest hepatomegaly in a patient with no other s y m p t o m and in good general condition. The results of the US and CT scans seemed to be in agreement with this hypothesis, thus the initial treatment with albendazole seemed justified. The rapid worsening of the child's general condition, the negative result of the blood tests and the following US scan indicated a pathology of the liver of nonparasitic origin [6, 9]. Also in view of the age and the symptoms of the child, a different diagnostic hypothesis could be m a d e considering other tumoural formations of the liver, such as: mesenchymal h a m a r t o m a , malignant mesenchymoma with a cystic component and cystic hepatoblastoma [3]. Histological examination of the excised mass demonstrated the existence of a malignant neoplasm which was characterized by a double cystic component, both epithelial and mesenchymal. The diagnostic hypothesis of a mixed hepatoblastoma was made, due to the presence of both types of tissue and considering the fact that this tum o u r is the most frequent malignant neoplasm of the liver in childhood. However, the epithelial component,
1. Cimarelli S, Virgilio A, Giovanuelli A (1987) Sarcoma primitivo embrionale del fegato. Presentazione di un caso. Minerva Chir 42 : 1427-1430 2. Cozzutto C, DeBernardi B, Comelli A (1981) Malignant mesenchymoma of the liver in children: a clinicopathological and ultrastructural study. Hum Pathol 12 : 481-485 3. De Maioribus AC, Lally PK, Sim K, Isaacs H, Mahour H (1990) Mesenchymal hamartoma of the liver. A 35-year review. Arch Surg 125:598-600 4. Federici S, Cuoghi D, Ceccarelli PL (1988) Structural analogies and differential diagnosis between benign and malignant mesenchymal neoplasms of the liver in childhood. Ital J Pediatr Surg Sci 2:11-15 5. Finegold M (1986) Pathology of neoplasia in children and adolescents. In: Bennington JL (ed) Major problems in pathology. W. B. Saunders, Philadelphia, vol 18, pp 360-363 6. Gurses H, Sungur R, Orkan K (1987) Ultrasound diagnosis of liver hydatid disease, Acta Radiol 28:161-163 7. Lack EE, Schloo BL, Azumi N (1991) Undifferentiated (embryonal) sarcoma of the liver. Clinical and pathologic study of 16 cases with emphasis on immunohistochemical features. Am J Surg Pathol 15 : 1-16 8. Leuschner I, Schmid D, Harms D (1990) Undifferentiated sarcoma of the liver in childhood: morphology, flow cytometry and literature review. Hum Pathol 21 : 68-76 9. Lewall D, Mc Corkell SJ (1985) Hepatic echinococcal cysts: sonographic appearance and classification. Radiology 155 : 773775 10. Marshall DG (1990) Malignant mesenchymoma of the liver in children. Letter comment. J Pediatr Surg 25 : 583 11. Newman KD, Schisgall R, Reaman G, Guzzetta PG (1989) Malignant mesenchymoma of the liver in children. J Pediatr Surg 24 : 781-783
491 12. Perilongo G, Carli M, Sainati L (1987) Undifferentiated (embryonal) sarcoma of the liver in childhood: results of a retrospective Italian study. Tumori 73 : 213-217 13. Randolph JG, Guzzetta PC (1986) Tumors of the liver. In: Welch KJ, et al (eds) Pediatric surgery. Year Book Medical Publisher, Chicago, pp 302-310 14. Smithson WA, Telander RL, Carney JA (1982) Mesenchymoma of the liver in childhood: five-year survival after combined-modality treatment. J Pediatr Surg 17 : 70-72 15. Steiner M, Bostrum B, Leonard AS (1989) Undifferentiated (embryonal) sarcoma of the liver. A clinicopathologic study of a survivor treated with combined technique therapy. Cancer 64:1318-1322
16. Stocker JT, Ishak KG (1978) Undifferentiated (embryonal) sarcoma of the liver. Report of 31 cases. Cancer 42:336-348 17. Stout AP (1948) Mesenchymoma, the mixed tumor of mesenchymal derivatives. Ann Surg 127 : 278-290 18. Ware R, Friedman HS, Filston HC, et al (1988) Childhood hepatic mesenchymoma: successful treatment with surgery and multiple-agent chemotherapy. Med Pediatr Oncol 16: 62-65 19. Weinberg AG, Finegold MJ (1983) Primary hepatic tumors of childhood. Hum Pathol 14 : 512-537 20. Case records of Massachusetts General Hospital. Case 19. (1990) N Engl J Med 322 : 213-217
