Primary liposarcoma of bone in an adolescent - A case report

We report the clinicopathologic and cytogenetic findings in an unusual case of primary liposarcoma of bone. A 16-year-old girl presented with a destru ctive, osteolytic tumor of the proximal humerus. Upon biopsy, the tumor was highly anaplastic and necrotizing and was initially considered to be consi stent with osteosarcoma. Following chemotherapy, there was 100% tumor necro sis in the resection specimen. Twenty-eight months later, solitary supracla vicular and pulmonary metastases appeared with the morphologic features of pleomorphic liposarcoma. Retrospective review of the bone biopsy showed sca ttered lipoblasts and no unequivocal malignant osteoid. Ghost-like remnants of necrotic liposarcoma were seen in the resection specimen. Cytogenetic a nalysis of a metastatic lesion showed complex karyotypic abnormalities. Awa reness of the existence of primary bone sarcomas with lipogenic differentia tion expands the differential diagnosis of malignant bone tumors including cases in the pediatric population. This is the first report of cytogenetic findings in this tumor.