|Year : 2013 | Volume
| Issue : 3 | Page : 305-307
Lipoblastoma: A rare benign, pediatric soft tissue tumor
Ghante Nagaraj Srinivas, Anitha B Chalageri, Anjana Gupta, Manjula Vijayanand
Department of Pathology, SRL Diagnostics - KCDC, Mysore, Karnataka, India
|Date of Web Publication||5-Jul-2013|
Anitha B Chalageri
Consultant Pathologist, SRL Diagnostics - KCDC, L 25/2A, Irwin Road, Mysore - 570 001, Karnataka
Source of Support: Management and Staff, SRL Diagnostics – KCDC,
Mysore., Conflict of Interest: None
We report a case of Lipoblastoma in a 4-year-old boy along with a brief review of literature. Lipoblastomas are rare benign tumors that arise from embryonic white fat. These lesions exhibit a wide range of cellular differentiation and maturation. A range of differentiation from unvacuolated spindle cells within the myxoid matrix to increasingly larger and more vacuolated cells to the mature adipocyte, can be noted at high power. These lesions are typically asymptomatic and most cases are diagnosed within the first decade of life. This case report tries to describe the importance of differentiating Lipoblastoma from myxoid Liposarcoma. Lipoblastomas when followed, gradually mature, with the disappearance of the spindle and myxoid elements.
Keywords: Adipocyte, adipose tumor, lipoblastoma, lipoblastomatosis, lipoblast, myxoid liposarcoma
|How to cite this article:|
Srinivas GN, Chalageri AB, Gupta A, Vijayanand M. Lipoblastoma: A rare benign, pediatric soft tissue tumor. Med J DY Patil Univ 2013;6:305-7
|How to cite this URL:|
Srinivas GN, Chalageri AB, Gupta A, Vijayanand M. Lipoblastoma: A rare benign, pediatric soft tissue tumor. Med J DY Patil Univ [serial online] 2013 [cited 2021 Apr 20];6:305-7. Available from: https://www.mjdrdypu.org/text.asp?2013/6/3/305/114660
| Introduction|| |
Lipoblastoma is predominantly a tumor of infancy, affecting principally males before the age of 3 years, although cases up to age 7 or 8 years are encountered rarely. , Fewer than 10% of all pediatric soft tissue tumors are adipose tumors, of which approximately 5%-30% are of lipoblastomatous type.  Most of them present as a superficial, circumscribed, slow-growing mass in the proximal part of a limb.  The average diameter is approximately 5.0 cm. Deeper lesions may be diffusely infiltrative in which case they are known as lipoblastomatosis.  We report a case of lipoblastoma in a 4-year-old boy and review the literature pertaining to the differential diagnosis.
| Case Report|| |
A 4-year-old boy presented with a mass on his left thigh that had been present for 4 months. Complete excision was performed without complications.
The gross specimen measured 8.0 × 4.0 × 3.0 cm. It was an encapsulated, lobulated, soft, grey yellow mass with a slimy cut surface, with grey yellow to grey white and myxoid areas [Figure 1]. Histologically a prominent lobular pattern was noted. Thin connective tissue septae separated the lobules. Varying degree of differentiation was seen within the lobules, ranging from small stellate cells without fat vacuoles to signet ring cells. All these were set in a richly vascular myxoid matrix. No atypical mitoses were seen. Maturation was seen at the center of the lobules. Adipocyte nuclei appeared more prominent and there was some variation in adipocyte size [Figure 2] and [Figure 3].
|Figure 2: Lobules with central variably sized mature adipocytes set in a vascular myxoid matrix with stellate cells (H and E stain, ×10)|
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|Figure 3: Mature adipocytes with prominent nuclei surrounded by myxoid matrix with unvacuolated spindle cells (H and E stain, ×40 )|
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A diagnosis of lipoblastoma was made.
| Discussion|| |
Jaffe coined the term "lipoblastoma" in 1926 to describe an atypical lipomatous lesion that consisted of cells resembling embryonic white fat. This term was intended to differentiate these lesions from common lipomas, which contain no lipoblasts. 
Lipoblastoma has a lobular architecture, the lobules being composed of mature and immature fat cells in varying degrees, separated by fibrous septa. The more immature lobules consist of primitive mesenchymal cells, lipoblasts, and small capillaries, all set in a myxoid stroma, highly reminiscent of myxoid liposarcoma except for absence of nuclear atypia. More mature lobules resemble lipoma except that the adipocyte nuclei appear more prominent and there is some variation in adipocyte size. Even in immature areas, mitoses are infrequent. 
On microscopy, an occasional lobule in a lipoblastoma may show an appearance resembling brown-fat. Small foci of extramedullary hematopoiesis are quite common. 
Lipoblastomatosis shows similar histology but differs by having an infiltrative margin.
Recurrence has been reported in 14%-25% of cases most often due to incomplete removal.  Recurrent lesions quite often show maturation toward a simple lipoma. 
Lipoblastomas are always benign and it is important to differentiate these lesions from myxoid liposarcomas. Myxoid liposarcomas are exceedingly rare in children under the age of 10 years. Principal clues for the diagnosis of lipoblastoma are striking lobulation, maturation toward the center of the lobules, and absence of nuclear atypia or atypical mitoses. 
Lipoblastoma often exhibits chromosome abnormalities at 8q11-13, whereas liposarcoma typically exhibits chromosome rearrangements in the region 12q14. ,
Lipoblastomas are benign tumors and no malignant degeneration has been documented. Recurrence has been reported in 14%-25% of cases,  usually due to incomplete resection or diffuse disease. Complete resection of lipoblastomas yields excellent prognosis. ,
| Conclusion|| |
Lipoblastomas are rare benign tumors most often seen in infants and young children. It is essential to differentiate these lesions from potentially malignant lipomatous tumors. Complete resection achieves optimal results, but recurrence is possible and close follow-up is essential.
| Acknowledgment|| |
We are thankful to all our laboratory staff for their technical help and support.
| References|| |
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|3.||Coffin CM. Adipose and myxoid tumors. In: Coffin CM, Dehner LP, O'Shea PA, editors. Pediatric soft tissue tumors: A clinical, pathological and therapeutic approach. New Salt Lake City, Utah: JA Majors Company; 1997. p. 254-76. |
|4.||Fletcher CD. Soft tissue tumors. In: Fletcher CD, editor. Diagnostic histopathology of tumors. 2 nd ed. Philadelphia: Harcourt Publishers limited, Churchill Livingstone; 2000. p. 1476-77. |
|5.||Jaffe RH. Recurrent lipomatous tumors of the groin: Liposarcoma and lipoma pseudomyxomatodes. Arch Pathol 1926;1:381-7. |
|6.||Mentzel T, Calonje E, Fletcher CD. Lipoblastoma and lipoblastomatosis: A clinicopathological study of 14 cases. Histopathology 1993;23:527-33. |
|7.||Van Meurs DP. The transformation of an embryonic lipoma to a common lipoma. Br J Surg 1947;34:282-4. |
|8.||Fletcher JA, Kozakewich HP, Schoenberg ML, Morton CC. Cytogenetic findings in pediatric adipose tumors: Consistent rearrangement of chromosome 8 in lipoblastoma. Genes Chromosomes Cancer 1993;6:24-9. |
|9.||Brandal P, Bjerkehagen B, Heim S. Rearrangement of chromosomal region 8q11-13 in lipomatous tumors: Correlation with lipoblastoma morphology. J Pathol 2006;208:388-94. |
[Figure 1], [Figure 2], [Figure 3]