MYXOID LIPOSARCOMA WITH CARTILAGINOUS DIFFERENTIATION

Common histologic variants of liposarcoma are readily recognized, Hist ologic classification might be difficult, however, when liposarcoma de monstrates cartilaginous differentiation, Although this phenomenon has previously been noted, it has not, to our knowledge, been reported as a specific pathologic entity, All three patients in the present study were men, ages 37, 42, and 63 years, Each presented with a solitary, enlarging mass of the thigh that was surgically excised. The tumors ra nged in size from 8 to 13 cm, Microscopically, each lesion displayed c haracteristic features of myxoid liposarcoma; in addition, all possess ed discrete, rounded foci of mature-appearing hyaline cartilage, One c ase displayed small foci showing chondrocyte atypia. No other patterns of mesenchymal differentiation were present. All patients received po stoperative radiation therapy, No recurrences or metastases have been identified (mean duration, 39 mo), Myxoid liposarcomas with cartilagin ous differentiation are of importance because they might be misdiagnos ed as malignant mesenchymoma. The latter, if not qualified as to histo logic grade, might be presumed to be a biologically more aggressive le sion, In addition, these lesions must be distinguished from two benign processes: chondroid lipoma and extraskeletal chondroma with lipoblas t-like cells, Additional studies of this uncommon variant of liposarco ma will be necessary to document further its status as a low-grade sar coma.