Lipoblastoma and lipoblastomatosis in infancy and childhood: Histopathologic, ultrastructural, and cytogenetic features

Lipoblastoma is a relatively rare tumor that occurs in infancy and early ch ildhood and arises from embryonic white fat. Although a benign tumor, lipob lastomas tend to recur and may resemble myxoid liposarcoma. The authors rep ort 26 cases over a 15-year period at Texas Children's Hospital. There was a slight female predilection (14F:12M). The most common symptom was a painl ess mass with or without increasing size. The trunk, extremities, head and neck, retroperitoneum, inguinal canal, peritoneal cavity, and lung were the tumor sites. Most tumors were circumscribed lipoblastomas and the minority were diffuse infiltrative lipoblastomatosis. Reexcision for residual or re current tumor was necessary more frequently in patients with lipoblastomato sis. Histopathologic examination and ultrastructural examination revealed c ellular neoplasms composed of immature adipocytes with relatively well-defi ned septa, frequent lipoblasts, a fine vascular network, and often a myxoid appearance resembling myxoid liposarcoma. Cytogenetics was performed in 4 cases with chromosome 8q abnormality being most common. The major concern w ith lipoblastoma in children is to completely excise the tumor to avoid lea ving residual tumor and to prevent recurrences, Confusion with myxoid lipos arcoma, well-differentiated liposarcoma, and typical lipomas may occur. Alt hough asymptomatic, lipoblastomas may cause dysfunction of other organ syst ems due to mass effect. Complete surgical excision with at least 2 years of follow-up is the preferred therapy.