Bone marrow involvement by subcutaneous panniculitis-like T-cell lymphoma: a report of three cases

Subcutaneous panniculitis-like T-cell lymphoma is a rare subtype of cutaneous T-cell lymphoma. Virtually all cases are confined to the subcutaneous adipose tissue. In this report, we describe the first small series of subcutaneous panniculitis-like T-cell lymphoma (three patients) with bone marrow involvement. All patients presented with skin or soft tissue nodules, fever, and constitutional symptoms, and were diagnosed with subcutaneous panniculitis-like T-cell lymphoma based on the characteristic morphologic and immunophenotypic features of the subcutaneous lesions. Bone marrow core biopsies in these cases showed focal involvement by lymphoma with pathologic features similar to those seen in the diagnostic biopsies. Our observations suggest bone marrow involvement by subcutaneous panniculitis-like T-cell lymphoma does occur, and can be identified histologically and confirmed using standard immunohistochemistry. Our findings raise awareness of bone marrow involvement in this rare entity. However, the incidence and significance of bone marrow involvement in subcutaneous panniculitis-like T-cell lymphoma requires further evaluation.