Subcutaneous myxoid and round cell liposarcoma.

Myxoid and round cell liposarcoma is a variant of liposarcoma characterized by a morphologic continuum in which tumor progression from low-grade myxoid to high-grade hypercellular or round cell areas may be observed. A 28-year old man presented with a painful skin colored subcutaneous mass on his left flank. The skin lesion was discovered about two months ago. Computed tomography revealed a well-defined tumor in the subcutaneous area without significant lymphadenopathy. A histopathologic study showed a nonencapsulated nodular growing tumor mass under the deep dermis composed of a mixture of atypical proliferating lipoblasts in a prominent myxoid stroma, occasional uniform round to oval shaped primitive nonlipogenic mesenchymal cells and plexiform, chicken wire shaped capillaries. Based on these findings, we diagnosed this case as myxoid and round cell liposarcoma. Because liposarcomas are large tumors of the deep subcutis or deeper soft tissue, they rarely come to the attention of the dermatologist. However, liposarcoma should be of concern, especially when rapid growing subcutaneous tumors are shown.