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Mesenchymal hamartoma of the liver
M e s e n c h y m a l H a m a r t o m a of the Liver By John G. Raffensperger, Frank Gonzalez-Crussi, and Thomas Skeehan Chicago, Illinois 9 Mesenchymal hamartoma is a benign, cystic lesion that arises from connective tissues of the portal tracts. It is most common in children under 5 years of age. The diagnosis can be suspected w h e n a relatively asymptomatic child has a large, smooth mass in the liver. Radionuclide scans demonstrate a solitary lesion, and on ultrasound there are cystic spaces and septa. These are perfectly benign lesions and may be simply enucleated.
by a combination of electrocoagulation and suture ligation of vessels. A formal lobectomy was performed in three children, and in one child the large mass was enucleated from the right lobe after ligation of the right portal vein, artery, and hepatic duct. PATHOLOGY
It is now possible to distinguish this lesion from other liver tumors preoperatively by clinical evaluation and noninvasive imaging techniques. When the diagnosis is suspected preoperatively and confirmed at operation, a mesenchymal hamartoma is best removed by enucleation or other lesser procedures rather than by formal hepatic lobectomy.
A l l o f t h e s e six m e s e n c h y m a l h a m a r t o m a s were encapsulated and sharply demarcated from n o r m a l liver tissue. T h e c u t s u r f a c e d e m o n strated cystic cavities with septa that correlated w i t h t h e u l t r a s o n i c i m a g e ( F i g . 3). T h e c y s t i c c a v i t i e s c o n t a i n e d c l e a r or s l i g h t l y t u r b i d fluid. O n e grossly r e s e m b l e d a h e m a n g i o m a , a n d another had a myxoid, multinodular appearance. M i c r o s c o p i c a l l y , all w e r e s i m i l a r . T h e r e was loose m y x o i d tissue c o n t a i n i n g b r a n c h i n g , c o m p r e s s e d bile ducts. T h e c y s t i c fluid c o m p r e s s e d the myxoid ground substance giving the tumor a s p o n g y or l a b y r i n t h i n e a p p e a r a n c e . T h e c o m p o n e n t tissues w e r e well d i f f e r e n t i a t e d w i t h no e v i d e n c e of c e l l u l a r a t y p i s m or i n c r e a s e d m i t o t i c activity.
MATERIALS AND METHODS
DISCUSSION
Six children have been operated on for hepatic rnesenchyreal hamartoma at The Children's Memorial Hospital during the past 15 years. Their clinical data, size of the tumor, and results are listed in Table 1. These were all essentially asymptomatic infants or young children who had large, smooth, nontender masses inseparable from the liver by palpation. These tumors were extremely large; one, in a 4-year-old girl, weighed 1280 g. Studies such as the intravenous (IV) pyelogram or gastrointestinal roentgenograms merely demonstrated organ displacement by the mass and were of no value in making a diagnosis. Radionuclide scanning was performed in four of our patients. These studies all demonstrated an intrahepatic mass with irregular but decreased uptake of the radionuclide (Fig. 1). A correct diagnosis of hamartoma was suspected on the basis of the scan alone in three of the four patients in whom it was performed. Ultrasonography was carried out only in our most recent patients. This study clearly demonstrated cystic spaces and septa, which correlated with the gross appearance of the lesion (Fig. 2). At operation, these lesions were smooth, tense but cystic, and clearly distinguishable from a lymphangioma or hemangioma. Despite their large size, there was no invasion of adjacent organs or the opposite lobe. There were, however, superficial enlarged vessels at the periphery of the mass. In two patients, the lesion was attached to the liver by a pedicle and removal was possible by transection of normal liver tissue
The liver contains a rich mixture of tissues derived from both mesenchymal and endodermal anlage. Hence, it is not surprising that a large variety of benign and malignant tumors arise within its substance. Many liver tumors unique to childhood, such as the teratoma, lymphangioma, hamartoma, and hemangioma, represent developmental anomalies rather than true tumors) The mesenchymal hamartoma has been given other terms and has been most often confused with lymphangioma, but it is a distinct clinical entity.2 The gross and microscopic structures of reported cases are identical to ours. Dehner et al has further defined mesenchymal
INDEX
WORDS:
Mesenchymal
hamartoma,
liver
tumor.
ESENCHYMAL HAMARTOMA of the
M liver is a benign, cystic developmental anomaly that affects infants and young children.
Journal of Pediatric Surgery, Vol. 18, No. 5 (October), 1983
From the Division o f Pediatric Surgery and Division o f Anatomic Pathology, The Children's Memorial Hospital, Northwestern University Medical School, Chicago, IlL Address reprint requests to John G. Raffensperger, MD, Children's Memorial Hospital, 2300 Children's Plaza, Chicago, IL 60614. 9 1983 Grune & Stratton, Inc.
oo22-3468/83/18o5~o135Ol.OO/O
585
586
RAFFENSPERGER, GONZALEZ-CRUSSIA, A N D SKEEHAN
Table 1. Hepatic Mesenchymal Hamartoma Data for S i x Children. Age 5 yr
Sex F
Symptoms Movable mass
Pathology 14.5 x 13 • 6 cm mass attached by
Followup Well at 11 yr
a broad pedicle 11 mo
F
Abdominal distention, palpable mass
17 •
14 mo
F
Hard abdomen, mass
pedunculated 10 x 15 cm mass
5~h mo
F
Irritable, large mass
6 . 5 x 5 . 5 • 5 cm mass
Well at 14 yr
15 mo
M
Smooth, nontender mass
13 x 1 7 c m m a s s
Well a t S y r
4 yr
F
Smooth, nontender mass
15 •
Well a t 6 m o
12 x 12 cm mass 9 1 0 g
14 x 8 c m m a s s
W e l l a t 1Oyr Well at 14 yr
hamartoma with electron microscopy. 3 They found that the loose myxomatous tumor tissue consisted of bands of collagen fibrils with interspersed fibroblasts and small blood vessels. The predominant element of the tumor is this mature mesenchyma, but there are also interspersed hepatocytes and bile ducts. These findings suggest that this lesion arises from the connective tissue of the portal tracts. The clinical features of the previously reported cases are similar in that the children were under 5 years of age and asymptomatic except for a large abdominal mass. 4 The progressive abdominal distention, however, may result in severe respiratory distress or life-threatening starvation. 5'6 The usual tests of liver function are normal or nonspecific. Arteriography has either been normal or has mistakenly led to the pre- and intraoperative diagnosis of malignancy. 7-9 In our own practice, we have abandoned arteriography because it contributes little to either a
correct diagnosis or to a determination of operability in children with liver tumors. Ultrasonography, combined with nuclear imaging, will reliably localize a tumor within the liver, determine if it is solid or cystic, and provide information concerning its vascularity. Typically, ultrasonography reveals a collection of cystic fluid-filled spaces with septa and some echogenic foci. loJJ The predominance of cysts is a good indication that the lesion is benign. Surgical resection is indicated because they grow to a large size and compress adjacent organs. Most reported cases, including our own, were removed by a formal hepatic lobectomy. Unfortunately, two deaths have been reported due to operative complications, and others were initially thought to be inoperable because of their huge size. 12 When the tumor is pedunculated, excision is simple. A small tumor deep within one lobe is also probably best removed by a formal hepatic lobectomy. However, a huge lesion deeply situated close to the vena cava or the hepatic veins or one that bulges across to the opposite lobe
Fig. 1. Radionuclide scan illustrating a mesenchymal hamartoma occupying the right lobe of the liver,
Fig. 2. Ultrasound examination which demonstrates septa and fluid w i t h i n t h e lesion.
MESENCHYMAL HAMARTOMA OF THE LIVER
587
REFERENCES
Fig. 3. Cut surface of the mesenchymal hamartoma shown in Fig. 2.
requires careful intraoperative thought. If there is d o u b t about the pathology, a generous biopsy a n d frozen section e x a m i n a t i o n is indicated. If the lesion is clearly b e n i g n a n d cystic, aspiration of fluid will reduce the bulk of the mass. Further, a m e s e n c h y m a l h a m a r t o m a or simple cyst m a y be simply enucleated by following the plane of the capsule with b l u n t dissection. W i t h care, there is less blood loss t h a n with formal lobectomy, n o r m a l liver tissue is saved, a n d very large t u m o r s become safely resectable,
1. Dehner LP: Hepatic tumors in the pediatric age group: A distinctive clinicopathologic spectrum. Perspect Pediatr Pathol 4:217-268, 1978 2. Edmondson HA: Differential diagnosis of tumors and tumor-like lesionsof liver in infancy and childhood. Am J Dis Child 9t:168, 1956 3. Dehner LP, Ewing SL, Sumner HW: Infantile mesenchymal hamartoma of the liver. Arch Pathol 99:379-382, 1975 4. lshida M, Tsuchida Y, Saito S, et ah Mesenchymal hamartoma of the liver. Case report and literature review. Ann Surg 164:175-182, 1966 5. Srouji MN, Chatten J, Sehulman WM, et ah Mesenchymal hamartoma of the liver in infants. Cancer 42:24832489, 1978 6. Silber DL, Soper RT, Kent T: Life threatening mesenehymal hamartoma of the liver. J Pediatr Surg 5:471-472, 1970 7. Kotzman H: Mesenchymal hamartoma of the liver. J Pediatr Surg 7:71, 1972 8. Ein S, Stephens CA: Benign liver tumors and cysts in childhood. J Pediatr Surg 9:847-851, 1974 9. Gilbert RF, Waugh DE, Clarke JS: Mesenchymal hamartoma of the liver. South Med J 71:530-532, 1978 10. Rosenbaum DM, Mindell HJ: Ultrasonographic findings in mesenchymal hamartoma of the liver. Radiology 138:425-427, 1981 11. Kaude JV, Felman AH, Hawkins IF: Ultrasonography in primary hepatic tumors in early childhood. Pediatr Radiol 9:77-83, 1980 12. Sutton CA, Eller JL: Mesenchymal hamartoma of the liver. Cancer 22:29-34, 1968
by a combination of electrocoagulation and suture ligation of vessels. A formal lobectomy was performed in three children, and in one child the large mass was enucleated from the right lobe after ligation of the right portal vein, artery, and hepatic duct. PATHOLOGY
It is now possible to distinguish this lesion from other liver tumors preoperatively by clinical evaluation and noninvasive imaging techniques. When the diagnosis is suspected preoperatively and confirmed at operation, a mesenchymal hamartoma is best removed by enucleation or other lesser procedures rather than by formal hepatic lobectomy.
A l l o f t h e s e six m e s e n c h y m a l h a m a r t o m a s were encapsulated and sharply demarcated from n o r m a l liver tissue. T h e c u t s u r f a c e d e m o n strated cystic cavities with septa that correlated w i t h t h e u l t r a s o n i c i m a g e ( F i g . 3). T h e c y s t i c c a v i t i e s c o n t a i n e d c l e a r or s l i g h t l y t u r b i d fluid. O n e grossly r e s e m b l e d a h e m a n g i o m a , a n d another had a myxoid, multinodular appearance. M i c r o s c o p i c a l l y , all w e r e s i m i l a r . T h e r e was loose m y x o i d tissue c o n t a i n i n g b r a n c h i n g , c o m p r e s s e d bile ducts. T h e c y s t i c fluid c o m p r e s s e d the myxoid ground substance giving the tumor a s p o n g y or l a b y r i n t h i n e a p p e a r a n c e . T h e c o m p o n e n t tissues w e r e well d i f f e r e n t i a t e d w i t h no e v i d e n c e of c e l l u l a r a t y p i s m or i n c r e a s e d m i t o t i c activity.
MATERIALS AND METHODS
DISCUSSION
Six children have been operated on for hepatic rnesenchyreal hamartoma at The Children's Memorial Hospital during the past 15 years. Their clinical data, size of the tumor, and results are listed in Table 1. These were all essentially asymptomatic infants or young children who had large, smooth, nontender masses inseparable from the liver by palpation. These tumors were extremely large; one, in a 4-year-old girl, weighed 1280 g. Studies such as the intravenous (IV) pyelogram or gastrointestinal roentgenograms merely demonstrated organ displacement by the mass and were of no value in making a diagnosis. Radionuclide scanning was performed in four of our patients. These studies all demonstrated an intrahepatic mass with irregular but decreased uptake of the radionuclide (Fig. 1). A correct diagnosis of hamartoma was suspected on the basis of the scan alone in three of the four patients in whom it was performed. Ultrasonography was carried out only in our most recent patients. This study clearly demonstrated cystic spaces and septa, which correlated with the gross appearance of the lesion (Fig. 2). At operation, these lesions were smooth, tense but cystic, and clearly distinguishable from a lymphangioma or hemangioma. Despite their large size, there was no invasion of adjacent organs or the opposite lobe. There were, however, superficial enlarged vessels at the periphery of the mass. In two patients, the lesion was attached to the liver by a pedicle and removal was possible by transection of normal liver tissue
The liver contains a rich mixture of tissues derived from both mesenchymal and endodermal anlage. Hence, it is not surprising that a large variety of benign and malignant tumors arise within its substance. Many liver tumors unique to childhood, such as the teratoma, lymphangioma, hamartoma, and hemangioma, represent developmental anomalies rather than true tumors) The mesenchymal hamartoma has been given other terms and has been most often confused with lymphangioma, but it is a distinct clinical entity.2 The gross and microscopic structures of reported cases are identical to ours. Dehner et al has further defined mesenchymal
INDEX
WORDS:
Mesenchymal
hamartoma,
liver
tumor.
ESENCHYMAL HAMARTOMA of the
M liver is a benign, cystic developmental anomaly that affects infants and young children.
Journal of Pediatric Surgery, Vol. 18, No. 5 (October), 1983
From the Division o f Pediatric Surgery and Division o f Anatomic Pathology, The Children's Memorial Hospital, Northwestern University Medical School, Chicago, IlL Address reprint requests to John G. Raffensperger, MD, Children's Memorial Hospital, 2300 Children's Plaza, Chicago, IL 60614. 9 1983 Grune & Stratton, Inc.
oo22-3468/83/18o5~o135Ol.OO/O
585
586
RAFFENSPERGER, GONZALEZ-CRUSSIA, A N D SKEEHAN
Table 1. Hepatic Mesenchymal Hamartoma Data for S i x Children. Age 5 yr
Sex F
Symptoms Movable mass
Pathology 14.5 x 13 • 6 cm mass attached by
Followup Well at 11 yr
a broad pedicle 11 mo
F
Abdominal distention, palpable mass
17 •
14 mo
F
Hard abdomen, mass
pedunculated 10 x 15 cm mass
5~h mo
F
Irritable, large mass
6 . 5 x 5 . 5 • 5 cm mass
Well at 14 yr
15 mo
M
Smooth, nontender mass
13 x 1 7 c m m a s s
Well a t S y r
4 yr
F
Smooth, nontender mass
15 •
Well a t 6 m o
12 x 12 cm mass 9 1 0 g
14 x 8 c m m a s s
W e l l a t 1Oyr Well at 14 yr
hamartoma with electron microscopy. 3 They found that the loose myxomatous tumor tissue consisted of bands of collagen fibrils with interspersed fibroblasts and small blood vessels. The predominant element of the tumor is this mature mesenchyma, but there are also interspersed hepatocytes and bile ducts. These findings suggest that this lesion arises from the connective tissue of the portal tracts. The clinical features of the previously reported cases are similar in that the children were under 5 years of age and asymptomatic except for a large abdominal mass. 4 The progressive abdominal distention, however, may result in severe respiratory distress or life-threatening starvation. 5'6 The usual tests of liver function are normal or nonspecific. Arteriography has either been normal or has mistakenly led to the pre- and intraoperative diagnosis of malignancy. 7-9 In our own practice, we have abandoned arteriography because it contributes little to either a
correct diagnosis or to a determination of operability in children with liver tumors. Ultrasonography, combined with nuclear imaging, will reliably localize a tumor within the liver, determine if it is solid or cystic, and provide information concerning its vascularity. Typically, ultrasonography reveals a collection of cystic fluid-filled spaces with septa and some echogenic foci. loJJ The predominance of cysts is a good indication that the lesion is benign. Surgical resection is indicated because they grow to a large size and compress adjacent organs. Most reported cases, including our own, were removed by a formal hepatic lobectomy. Unfortunately, two deaths have been reported due to operative complications, and others were initially thought to be inoperable because of their huge size. 12 When the tumor is pedunculated, excision is simple. A small tumor deep within one lobe is also probably best removed by a formal hepatic lobectomy. However, a huge lesion deeply situated close to the vena cava or the hepatic veins or one that bulges across to the opposite lobe
Fig. 1. Radionuclide scan illustrating a mesenchymal hamartoma occupying the right lobe of the liver,
Fig. 2. Ultrasound examination which demonstrates septa and fluid w i t h i n t h e lesion.
MESENCHYMAL HAMARTOMA OF THE LIVER
587
REFERENCES
Fig. 3. Cut surface of the mesenchymal hamartoma shown in Fig. 2.
requires careful intraoperative thought. If there is d o u b t about the pathology, a generous biopsy a n d frozen section e x a m i n a t i o n is indicated. If the lesion is clearly b e n i g n a n d cystic, aspiration of fluid will reduce the bulk of the mass. Further, a m e s e n c h y m a l h a m a r t o m a or simple cyst m a y be simply enucleated by following the plane of the capsule with b l u n t dissection. W i t h care, there is less blood loss t h a n with formal lobectomy, n o r m a l liver tissue is saved, a n d very large t u m o r s become safely resectable,
1. Dehner LP: Hepatic tumors in the pediatric age group: A distinctive clinicopathologic spectrum. Perspect Pediatr Pathol 4:217-268, 1978 2. Edmondson HA: Differential diagnosis of tumors and tumor-like lesionsof liver in infancy and childhood. Am J Dis Child 9t:168, 1956 3. Dehner LP, Ewing SL, Sumner HW: Infantile mesenchymal hamartoma of the liver. Arch Pathol 99:379-382, 1975 4. lshida M, Tsuchida Y, Saito S, et ah Mesenchymal hamartoma of the liver. Case report and literature review. Ann Surg 164:175-182, 1966 5. Srouji MN, Chatten J, Sehulman WM, et ah Mesenchymal hamartoma of the liver in infants. Cancer 42:24832489, 1978 6. Silber DL, Soper RT, Kent T: Life threatening mesenehymal hamartoma of the liver. J Pediatr Surg 5:471-472, 1970 7. Kotzman H: Mesenchymal hamartoma of the liver. J Pediatr Surg 7:71, 1972 8. Ein S, Stephens CA: Benign liver tumors and cysts in childhood. J Pediatr Surg 9:847-851, 1974 9. Gilbert RF, Waugh DE, Clarke JS: Mesenchymal hamartoma of the liver. South Med J 71:530-532, 1978 10. Rosenbaum DM, Mindell HJ: Ultrasonographic findings in mesenchymal hamartoma of the liver. Radiology 138:425-427, 1981 11. Kaude JV, Felman AH, Hawkins IF: Ultrasonography in primary hepatic tumors in early childhood. Pediatr Radiol 9:77-83, 1980 12. Sutton CA, Eller JL: Mesenchymal hamartoma of the liver. Cancer 22:29-34, 1968