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Lipoblastoma in infants and children
Lipoblastoma in Infants and Children By Gustavo Stringel, Barry Shandling, Kent Mancer, and Sigmund H. Ein Toronto, Ontario, Canada 9 Lipoblastoma and lipoblastomatosis are rare benign t u m o r s of e m b r y o n a l fat w i t h a t e n d e n c y t o local invasion but not to metastasize, To date, t h e r e have been 6 0 cases described in the international literature. T h e r e has never been a r e p o r t in a child older than 8 yr. The main clinical characteristics are the presentation, usually b e l o w 3 yr of age, the rapid g r o w t h of the mass and the peripheral location, mainly in the e x t r e m i t i e s . Although C T scan m a y s h o w a f a t t y t u m o r , t h e r e is no single t e s t t o m a k e the differential diagnosis (which includes benign lipoma, liposarcoma and myxoliposarcoma) and the t r e a t m e n t should be based on clinical findings. W e have t r e a t e d four patients w i t h this condition. T w o w e r e intrathoracic, one was intraperitoneal, and one was a t u m o r of the upper arm, All p r e s e n t e d as rapidly-growing t u m o r s and w e r e clinically assumed to be malignant. W e r e c o m m e n d c o m p l e t e but conservative excision of the tumor; t h e r e are r e p o r t e d recurrences a f t e r inadequate excision. This is a benign t u m o r and radical cancer surgery should be avoided. I N D E X W O R D : Lipoblastoma.
L
IPOBLASTOMA embryonal
is
fat that
a
rare
occurs
tumor
almost
of
exclu-
pathology report was vascular lipoma. Ten months later the child was readmitted with an upper respiratory infection and a recurrence of the mass in the previously treated area. The mother had noticed the recurrence 1 mo after discharge. Chest x-ray at that time showed a large mass in the left pleural space that was thought to be malignant. Other investigations including a barium swallow and a bone marrow examination were normal. At surgery, the superficial lesion was locally excised and a thoracotomy was also performed, revealing a well-encapsulated fatty tumor measuring 8 x 6 x 7 cm. Pathology report was again vascular lipoma. Recently, this case was reviewed and reclassified as a lipoblastoma. Fourteen years later the patient has no evidence of recurrence.
Case 2 An 8-mo-old boy had a 12-day history of rapid swelling in the right deltoid area. Sarcoma was the initial consideration. Laboratory investigations were normal and no metastases were found. X-ray of the shoulder showed a well-circumscribed soft tissue tumor arising from the proximal end of the humerus. CT scan demonstrated a fatty tumor compatible with liposarcoma or lipoma. At surgery, an encapsulated Iobulated tumor measuring 5 x 5 • 2 cm was completely removed from beneath the deltoid muscle. Pathology report was lipoblastoma. Follow-up after 1 yr showed no recurrence.
s i v e l y in i n f a n t s a n d c h i l d r e n . ~-8 S i n c e t h e r e p o r t b y V e l l i o s e t al. in 1 9 5 8 , 9 l i p o b l a s t o m a t o s i s been recognized other
benign
as an entity
or malignant
that
has
differs from
tumors
of adipose
t i s s u e . T h i s t u m o r p r e s e n t s in t w o f o r m s : a l o c a l ized well-circumscribed a multicentric
lesion (lipoblastoma),
type (lipoblastomatosis).
or
~7
MATERIALS AND METHODS Four cases of lipoblastoma treated at the Hospital for Sick Children in Toronto are reported and 56 other cases from the international literature were reviewed. The clinical presentation, laboratory findings, radiologic investigations, and the role of CT scanning were analyzed to determine which of these parameters are useful in making the preoperative diagnosis of this rare tumor. Surgical treatment, pathological findings, and follow-up were also reviewed.
Case 3 A 13-mo-old boy presented with a 3-mo history of rapid and progressive abdominal distention. An abdominal mass in the right side of the abdomen was palpable. Laboratory investigations were normal. Ultrasound confirmed the presence of this mass, an IVP showed a large soft tissue mass displacing the right kidney upward and barium studies also demonstrated displacement of the stomach and duodenum. CT scan showed a large fatty tumor in the right side of the abdomen. At laparotomy, a large solid lobulated mass was found arising from the mesentery three feet from the ileocecal valve; this tumor was excised including 26 cm of small bowel. The mass measured 17 cm in diameter and weighed 1375 g; microscopically it was formed by spindle cells and fat cells with a prominent network of capillaries and was diagnosed as lipoblastoma. Follow-up after one year showed no evidence of recurrence.
CASE REPORTS (Table 1) Case 1 A 4-mo-old boy presented with a rapidly growing firm mass over the sixth rib in the left posterior axillary line. Laboratory investigations and initial chest x-ray were normal. At surgery, he was found to have a mass measuring 2.5 • 2.5 x 1-cm (underneath the latissimus dorsi) arising from beneath the inferior margin of the sixth rib. The initial
Journat of Pediatric Surgery, Vol. ~7, No. 3 (June), 1982
From The Division o f General Surgery and Department o f Pathology, The Hospital for Sick Children, Toronto, Ontario, Canada. Address reprint requests to Dr. G. Stringel, Children's Hospital o f Eastern Ontario, 401 Smyth Road, Ottawa, Ontario KI H 8LI, Canada. 9 1982 by Grune & Stratton, Inc. 0022-3468/82/1703~9012501.00/0
277
278
STRINGEL ET AL.
Table 1. Summary of Cases Sex
Age (mo)
Case 1
M
4
Case 2 Case 3
M M
8 13
Case 4
M
6'h
Size (cm)
Location Chest wall Intrathoracic Right deltoid Mesentery
2~ • 2'/~ 8 • 6 5 17
Intrathoracic
10
Case 4 A 6~/2-mo-oldboy had a 3-mo history of recurrent upper respiratory infection. Chest x-ray showed a large mass in the left hemithorax; previous chest x-ray done at 2 mo of age was normal. CT scan demonstrated a left lower thoracic solid tumor containing a large amount of fat. All laboratory investigations were normal. Left thoracotomy was performed and a solid soft fatty tumor was found and completely removed. This mass was arising from the region of the upper lobe bronchus and was supplied by a branch of the pulmonary artery. Macroscopically this tumor was a lobulated, encapsulated fatty mass measuring 10 cm in diameter and 1 cm in thickness and weighed 80 g. Microscopically this tumor was formed by immature adipose tissue arranged in Iobules separated by thin fibrous bands. The tumor cells showed vacuoles of different sizes, large vesicular nuclei with moderate mitotic activity and a prominent network of capillaries; it also showed evidence of extramedullary hemopoesis. Followup after 1 yr showed no recurrence. PATHOLOGY In our cases, the t u m o r s were all e n c a p s u l a t e d with a thin fibrous capsule, lobulated, yellowwhite in color and of soft consistency. S o m e of the tissue showed line septae and a shiny cut surface. O n e t u m o r had a central a r e a of necrosis a n d a n o t h e r showed small fluid-filled cysts. Histological a p p e a r a n c e was s i m i l a r to previously reported cases. ~ 4,6 9 S t r a n d s of fibrous tissue s e p a r a t e d rounded foci of lipoblasts within m a t u r e fatty tissue. Also present was a prominent c a p i l l a r y network. T u m o r cells showed vacuoles of varying sizes with some of the single vacuoles in the larger cells a p p r o a c h i n g the size of m a t u r e fat cells. S m a l l e r t u m o r cells had m u l t i p l e small droplets while some of the less m a t u r e cells had large vesicular nuclei. Spindles h a p e d and stellate cells s u r r o u n d e d by a myxoid s t r o m a were at the p e r i p h e r y of the lobules. In one o f our cases, t h e r e was c o n s i d e r a b l e fibroblastic proliferation and f o r m a t i o n of collagen; a n o t h e r had islands of n o r m o b l a s t s indicative of e x t r a m e d u l l a r y hemopoesis, and others showed m o d e r a t e mitotic activity (2 to 3 mitoses per high-power field). A f t e r c o m p l e t e excision there was no recur-
rence in t h r e e of the four cases in this series. In case 1, the single r e c u r r e n t t u m o r was adeq u a t e l y excised the second t i m e and there has been no further recurrence. DISCUSSION L i p o b l a s t o m a and lipoblastomatosis a r e r a r e t u m o r s derived from e m b r y o n a l fat; they have been r e g a r d e d as t u m o r s t h a t occur almost exclusively in children, m a i n l y under 1 yr of age. T h e oldest r e p o r t e d case in the English l i t e r a t u r e has been 8 yr of age, ~but S t o u t and L a t t e s refer to six cases in their personal files t h a t occurred in adults, s C a r c a s s o n n e et al. also reported a 63yr-old m a n with a l i p o b l a s t o m a of the mesentery. 8 In previous reports, lipoblastomas have been noted to have a predilection for sites that possess the most primitive adipose tissue in the newborn: axilla, neck, chest wall, and prevertebral soft tissue; 4 however, in 35 cases reported by C h u n g and Enzinger, 70% occurred in the extremities. ~ T h e r e has been g r e a t confusion in the literature in classification of this t u m o r and it was not until 1958 when Vellios et al. 9 described this entity as " l i p o b l a s t o m a t o s i s " that this t u m o r has become recognized as a benign t u m o r of fatty e m b r y o n a l tissue, c a p a b l e of invading surrounding structures but lacking m e t a s t a t i c potential. In 1959 K a u f f m a n and S t o u t regarded lipob l a s t o m a as a benign t u m o r and they recommended total excision to avoid recurrence. 3 O t h e r a u t h o r s have considered lipoblastoma as a t u m o r of i n t e r m e d i a t e m a l i g n a n c y , between lipoma and liposarcoma, ~ and postulated that if the t u m o r is not c o m p l e t e l y excised it m a y progress to liposarcoma, although liposarcoma is e x t r e m e l y rare in childhood. T h e r e has been no evidence to support this viewpoint. In the 56 world cases prior to our four patients, 70% occurred in the e x t r e m i t i e s as outlined in Figure 1. T h e sex ratio was 3:1 male to female and the most c o m m o n age of presentation was under 1 yr; 55% of t u m o r s occurred in this age group alone. T h e t u m o r is r a r e after 3 yr of age and in the English l a n g u a g e l i t e r a t u r e there a r e only two cases reported a f t e r the age of 6 yr with none reported a f t e r age 8 ( F i g u r e 2). Clinically, it is difficult to differentiate lipob l a s t o m a from a m a l i g n a n t tumor, especially embryonal rhabdomyosarcoma. Liposarcoma must be also considered in the differential diag-
LIPOBLASTOMA
279
L O C A T I O N OF THE TUMOR
HEAD I UPPER EXTREMITY | I 13(23%) J k 1 CHEEK 1 ! Shoulder 3 ~ r ~ NECK 5 Upper arm ~ Elbow.l~ I Mediastinum 2" :1 4 Axilla'~ Hand Chest wall 1 ~REIROPERITONEUM
/
2
-Buttock 8
)
,Back 4
VuJvQ
TRUNK 8
Thigh 1
LOWER EXTREMITY 26 (46%) Lower l e ~ ~ TOTAL 56 Fig. 1
nosis but that tumor is extremely rare in children under 3 yr of age. Benign tumors, particularly lipoma and hibernoma have similar clinical features except for slower growth. 9 Laboratory investigations are usually normal. Plain radiographs disclose a soft tissue mass with NUMBER OF PATIENTS 40-
M--37 F --19
20-30-iii 56
o
2
3
4
5
AGE (years) Fig. 2
6
7
8
no calcification; x-ray examination with contrast material may be useful. CT scanning was done in three of our cases and was found to be a very useful examination because it not only demonstrated the limits of the mass, but it also showed that it was formed mainly of low density tissue suggestive of fat. Angi0graphy is useful only if the CT scan does not suggest the diagnosis and then only if the tumor is large and may be difficult to excise completely. In our experience, ultrasound helped to outline the mass but did not supply any additional information. At surgery, the tumor appears as a soft lobulated mass and can easily be excised completely. Although extirpation should be complete, a wide "cancer" type of operation is not necessary and may be mutilating, especially in an infant. Metastases have not been reported, but local recurrence is a distinct possibility, so that careful follow-up is essential. Recurrence is not considered likely after an interval of 12 mo.
280
STRINGEL ET AL.
REFERENCES
1. Chung EB, Enzinger FM: Benign lipoblastomatosis-An analysis of 35 cases. Cancer 32:482 492, 1973 2. Gibbs MD, Soule EH, Hayles AB, et al: Lipoblastomatosis: A tumor of children. Pediatrics 60:235 238, 1977 3. Kauffman SL, Stout AP: Lipoblastic tumors of children. Cancer 12:912 925, 1959 4. Tabrisky J, Rowe JH, Christis SG, et al: Benign mediastinal lipoblastomatosis. J Pediatr Surg 9:(3)399-401, 1974 5. Stout AP, Lattes R: Tumors of the soft tissue second series. Fascicle I Armed Forces Institute of Pathology, pp 52-57, 1967
6. Langloh JT, Reing CM, Chun BK, et al: Lipoblastomatosis. J Bone Joint Surg 60:130 132, 1978 7. Yoshida I, Eajoji M: Benign lipoblastomatosis. A clinicopathological study. Fukoka Acta Medica 67(1):1-9, 1976 8. Carcassonne F, Bonneau H, Peschard J J, et al: Le Lipoblastome: A Propos d'une observation de lipoblastoma du mesentere. J lnt Coil Surg 42(3):311 331, 1964 9. Vellios F, Baez J, Shumacker HB: Lipoblastomatosis. A tumor of fetal fat different from hibernoma. Am J Pathol 34(No6):1149 1159,1958
L
IPOBLASTOMA embryonal
is
fat that
a
rare
occurs
tumor
almost
of
exclu-
pathology report was vascular lipoma. Ten months later the child was readmitted with an upper respiratory infection and a recurrence of the mass in the previously treated area. The mother had noticed the recurrence 1 mo after discharge. Chest x-ray at that time showed a large mass in the left pleural space that was thought to be malignant. Other investigations including a barium swallow and a bone marrow examination were normal. At surgery, the superficial lesion was locally excised and a thoracotomy was also performed, revealing a well-encapsulated fatty tumor measuring 8 x 6 x 7 cm. Pathology report was again vascular lipoma. Recently, this case was reviewed and reclassified as a lipoblastoma. Fourteen years later the patient has no evidence of recurrence.
Case 2 An 8-mo-old boy had a 12-day history of rapid swelling in the right deltoid area. Sarcoma was the initial consideration. Laboratory investigations were normal and no metastases were found. X-ray of the shoulder showed a well-circumscribed soft tissue tumor arising from the proximal end of the humerus. CT scan demonstrated a fatty tumor compatible with liposarcoma or lipoma. At surgery, an encapsulated Iobulated tumor measuring 5 x 5 • 2 cm was completely removed from beneath the deltoid muscle. Pathology report was lipoblastoma. Follow-up after 1 yr showed no recurrence.
s i v e l y in i n f a n t s a n d c h i l d r e n . ~-8 S i n c e t h e r e p o r t b y V e l l i o s e t al. in 1 9 5 8 , 9 l i p o b l a s t o m a t o s i s been recognized other
benign
as an entity
or malignant
that
has
differs from
tumors
of adipose
t i s s u e . T h i s t u m o r p r e s e n t s in t w o f o r m s : a l o c a l ized well-circumscribed a multicentric
lesion (lipoblastoma),
type (lipoblastomatosis).
or
~7
MATERIALS AND METHODS Four cases of lipoblastoma treated at the Hospital for Sick Children in Toronto are reported and 56 other cases from the international literature were reviewed. The clinical presentation, laboratory findings, radiologic investigations, and the role of CT scanning were analyzed to determine which of these parameters are useful in making the preoperative diagnosis of this rare tumor. Surgical treatment, pathological findings, and follow-up were also reviewed.
Case 3 A 13-mo-old boy presented with a 3-mo history of rapid and progressive abdominal distention. An abdominal mass in the right side of the abdomen was palpable. Laboratory investigations were normal. Ultrasound confirmed the presence of this mass, an IVP showed a large soft tissue mass displacing the right kidney upward and barium studies also demonstrated displacement of the stomach and duodenum. CT scan showed a large fatty tumor in the right side of the abdomen. At laparotomy, a large solid lobulated mass was found arising from the mesentery three feet from the ileocecal valve; this tumor was excised including 26 cm of small bowel. The mass measured 17 cm in diameter and weighed 1375 g; microscopically it was formed by spindle cells and fat cells with a prominent network of capillaries and was diagnosed as lipoblastoma. Follow-up after one year showed no evidence of recurrence.
CASE REPORTS (Table 1) Case 1 A 4-mo-old boy presented with a rapidly growing firm mass over the sixth rib in the left posterior axillary line. Laboratory investigations and initial chest x-ray were normal. At surgery, he was found to have a mass measuring 2.5 • 2.5 x 1-cm (underneath the latissimus dorsi) arising from beneath the inferior margin of the sixth rib. The initial
Journat of Pediatric Surgery, Vol. ~7, No. 3 (June), 1982
From The Division o f General Surgery and Department o f Pathology, The Hospital for Sick Children, Toronto, Ontario, Canada. Address reprint requests to Dr. G. Stringel, Children's Hospital o f Eastern Ontario, 401 Smyth Road, Ottawa, Ontario KI H 8LI, Canada. 9 1982 by Grune & Stratton, Inc. 0022-3468/82/1703~9012501.00/0
277
278
STRINGEL ET AL.
Table 1. Summary of Cases Sex
Age (mo)
Case 1
M
4
Case 2 Case 3
M M
8 13
Case 4
M
6'h
Size (cm)
Location Chest wall Intrathoracic Right deltoid Mesentery
2~ • 2'/~ 8 • 6 5 17
Intrathoracic
10
Case 4 A 6~/2-mo-oldboy had a 3-mo history of recurrent upper respiratory infection. Chest x-ray showed a large mass in the left hemithorax; previous chest x-ray done at 2 mo of age was normal. CT scan demonstrated a left lower thoracic solid tumor containing a large amount of fat. All laboratory investigations were normal. Left thoracotomy was performed and a solid soft fatty tumor was found and completely removed. This mass was arising from the region of the upper lobe bronchus and was supplied by a branch of the pulmonary artery. Macroscopically this tumor was a lobulated, encapsulated fatty mass measuring 10 cm in diameter and 1 cm in thickness and weighed 80 g. Microscopically this tumor was formed by immature adipose tissue arranged in Iobules separated by thin fibrous bands. The tumor cells showed vacuoles of different sizes, large vesicular nuclei with moderate mitotic activity and a prominent network of capillaries; it also showed evidence of extramedullary hemopoesis. Followup after 1 yr showed no recurrence. PATHOLOGY In our cases, the t u m o r s were all e n c a p s u l a t e d with a thin fibrous capsule, lobulated, yellowwhite in color and of soft consistency. S o m e of the tissue showed line septae and a shiny cut surface. O n e t u m o r had a central a r e a of necrosis a n d a n o t h e r showed small fluid-filled cysts. Histological a p p e a r a n c e was s i m i l a r to previously reported cases. ~ 4,6 9 S t r a n d s of fibrous tissue s e p a r a t e d rounded foci of lipoblasts within m a t u r e fatty tissue. Also present was a prominent c a p i l l a r y network. T u m o r cells showed vacuoles of varying sizes with some of the single vacuoles in the larger cells a p p r o a c h i n g the size of m a t u r e fat cells. S m a l l e r t u m o r cells had m u l t i p l e small droplets while some of the less m a t u r e cells had large vesicular nuclei. Spindles h a p e d and stellate cells s u r r o u n d e d by a myxoid s t r o m a were at the p e r i p h e r y of the lobules. In one o f our cases, t h e r e was c o n s i d e r a b l e fibroblastic proliferation and f o r m a t i o n of collagen; a n o t h e r had islands of n o r m o b l a s t s indicative of e x t r a m e d u l l a r y hemopoesis, and others showed m o d e r a t e mitotic activity (2 to 3 mitoses per high-power field). A f t e r c o m p l e t e excision there was no recur-
rence in t h r e e of the four cases in this series. In case 1, the single r e c u r r e n t t u m o r was adeq u a t e l y excised the second t i m e and there has been no further recurrence. DISCUSSION L i p o b l a s t o m a and lipoblastomatosis a r e r a r e t u m o r s derived from e m b r y o n a l fat; they have been r e g a r d e d as t u m o r s t h a t occur almost exclusively in children, m a i n l y under 1 yr of age. T h e oldest r e p o r t e d case in the English l i t e r a t u r e has been 8 yr of age, ~but S t o u t and L a t t e s refer to six cases in their personal files t h a t occurred in adults, s C a r c a s s o n n e et al. also reported a 63yr-old m a n with a l i p o b l a s t o m a of the mesentery. 8 In previous reports, lipoblastomas have been noted to have a predilection for sites that possess the most primitive adipose tissue in the newborn: axilla, neck, chest wall, and prevertebral soft tissue; 4 however, in 35 cases reported by C h u n g and Enzinger, 70% occurred in the extremities. ~ T h e r e has been g r e a t confusion in the literature in classification of this t u m o r and it was not until 1958 when Vellios et al. 9 described this entity as " l i p o b l a s t o m a t o s i s " that this t u m o r has become recognized as a benign t u m o r of fatty e m b r y o n a l tissue, c a p a b l e of invading surrounding structures but lacking m e t a s t a t i c potential. In 1959 K a u f f m a n and S t o u t regarded lipob l a s t o m a as a benign t u m o r and they recommended total excision to avoid recurrence. 3 O t h e r a u t h o r s have considered lipoblastoma as a t u m o r of i n t e r m e d i a t e m a l i g n a n c y , between lipoma and liposarcoma, ~ and postulated that if the t u m o r is not c o m p l e t e l y excised it m a y progress to liposarcoma, although liposarcoma is e x t r e m e l y rare in childhood. T h e r e has been no evidence to support this viewpoint. In the 56 world cases prior to our four patients, 70% occurred in the e x t r e m i t i e s as outlined in Figure 1. T h e sex ratio was 3:1 male to female and the most c o m m o n age of presentation was under 1 yr; 55% of t u m o r s occurred in this age group alone. T h e t u m o r is r a r e after 3 yr of age and in the English l a n g u a g e l i t e r a t u r e there a r e only two cases reported a f t e r the age of 6 yr with none reported a f t e r age 8 ( F i g u r e 2). Clinically, it is difficult to differentiate lipob l a s t o m a from a m a l i g n a n t tumor, especially embryonal rhabdomyosarcoma. Liposarcoma must be also considered in the differential diag-
LIPOBLASTOMA
279
L O C A T I O N OF THE TUMOR
HEAD I UPPER EXTREMITY | I 13(23%) J k 1 CHEEK 1 ! Shoulder 3 ~ r ~ NECK 5 Upper arm ~ Elbow.l~ I Mediastinum 2" :1 4 Axilla'~ Hand Chest wall 1 ~REIROPERITONEUM
/
2
-Buttock 8
)
,Back 4
VuJvQ
TRUNK 8
Thigh 1
LOWER EXTREMITY 26 (46%) Lower l e ~ ~ TOTAL 56 Fig. 1
nosis but that tumor is extremely rare in children under 3 yr of age. Benign tumors, particularly lipoma and hibernoma have similar clinical features except for slower growth. 9 Laboratory investigations are usually normal. Plain radiographs disclose a soft tissue mass with NUMBER OF PATIENTS 40-
M--37 F --19
20-30-iii 56
o
2
3
4
5
AGE (years) Fig. 2
6
7
8
no calcification; x-ray examination with contrast material may be useful. CT scanning was done in three of our cases and was found to be a very useful examination because it not only demonstrated the limits of the mass, but it also showed that it was formed mainly of low density tissue suggestive of fat. Angi0graphy is useful only if the CT scan does not suggest the diagnosis and then only if the tumor is large and may be difficult to excise completely. In our experience, ultrasound helped to outline the mass but did not supply any additional information. At surgery, the tumor appears as a soft lobulated mass and can easily be excised completely. Although extirpation should be complete, a wide "cancer" type of operation is not necessary and may be mutilating, especially in an infant. Metastases have not been reported, but local recurrence is a distinct possibility, so that careful follow-up is essential. Recurrence is not considered likely after an interval of 12 mo.
280
STRINGEL ET AL.
REFERENCES
1. Chung EB, Enzinger FM: Benign lipoblastomatosis-An analysis of 35 cases. Cancer 32:482 492, 1973 2. Gibbs MD, Soule EH, Hayles AB, et al: Lipoblastomatosis: A tumor of children. Pediatrics 60:235 238, 1977 3. Kauffman SL, Stout AP: Lipoblastic tumors of children. Cancer 12:912 925, 1959 4. Tabrisky J, Rowe JH, Christis SG, et al: Benign mediastinal lipoblastomatosis. J Pediatr Surg 9:(3)399-401, 1974 5. Stout AP, Lattes R: Tumors of the soft tissue second series. Fascicle I Armed Forces Institute of Pathology, pp 52-57, 1967
6. Langloh JT, Reing CM, Chun BK, et al: Lipoblastomatosis. J Bone Joint Surg 60:130 132, 1978 7. Yoshida I, Eajoji M: Benign lipoblastomatosis. A clinicopathological study. Fukoka Acta Medica 67(1):1-9, 1976 8. Carcassonne F, Bonneau H, Peschard J J, et al: Le Lipoblastome: A Propos d'une observation de lipoblastoma du mesentere. J lnt Coil Surg 42(3):311 331, 1964 9. Vellios F, Baez J, Shumacker HB: Lipoblastomatosis. A tumor of fetal fat different from hibernoma. Am J Pathol 34(No6):1149 1159,1958