LIPOBLASTOMA LIPOBLASTOMATOSIS - A CLINICOPATHOLOGICAL STUDY OF 25 TUMORS/

Lipoblastoma/lipoblastomatosis is an uncommon benign adipose tissue tu mor of children. Since 1958, 25 of these tumors from 24 patients have been reviewed in the Department of Pathology at The Children's Hospita l of Philadelphia. Tumors were resected from 19 boys (79%) and five gi rls, and 20 patients (84%) were less than or equal to 5 years of age a t diagnosis. Twenty-three tumors presented as painless superficial sof t-tissue masses; one tumor was retroperitoneal and was discovered beca use of vomiting; one hand tumor was present at birth. Tumors occurred in an extremity (n = 11 patients), the head and neck (n = 5), groin (n = 2), axilla (n = 2), back (n = 1), chest (n = 1), flank (n = 1), lab ia (n = 1), and retroperitoneum (n = 1). Thirteen tumors occurred on t he left side, and five occurred on the right. Lesions measured 1.0-21. 0 cm in greatest dimension; 15 of 25 (60%) measured less than or equal to 5.0 cm. The largest (retroperitoneal) tumor weighed 450 g. Eleven tumors were discrete lipoblastoma, and 14 had irregular margins (lipob lastomatosis). Microscopically, the tumors displayed adipocytes in dif ferent stages of maturation; lobules bordered by septae that were cell ular in 11 cases; prominent blood vessels in 19 cases; and myxoid foci in 13 cases. Chart review of 22 patients showed that one tumor recurr ed 4 years after resection, one tumor recurred after 7 years as fibrol ipoma; and one incompletely resected tumor enlarged and at second rese ction was lipoma. There were no metastases. Three patients also had he mangioma. Juvenile aponeurotic fibroma occurred in one patient near th e site of resection of a lipoblastoma 4 years earlier. We conclude tha t lipoblastoma/lipoblastomatosis behaves benignly, occurs in both supe rficial and deep sites, occasionally attains large size, may mature, c an recur, and may be associated with other benign soft-tissue lesions. Complete surgical excision is the treatment of choice.