CD4+ CD56+ hematodermic/plasmacytoid dendritic cell tumor with response to pralatrexate

The CD4+ CD56+ hematodermic/plasmacytoid dendritic cell tumor is a rare, highly aggressive, systemic neoplasm for which effective therapies have not yet been established. These tumors express CD4, CD56, CD123, and T-cell leukemia/lymphoma (TCL)-1 and are clinically characterized by cutaneous involvement with spread to bone marrow and blood, and poor prognosis with current chemotherapy regimens. We describe a Caucasian woman who presented with plasmacytoid dendritic cell tumor, but an absence of systemic symptoms. Clinically, multiple cutaneous lesions were brown to violaceous firm nodules on the face, arms, and trunk. The patient underwent two courses of cyclophosphamide, Adriamycin, vincristine, and prednisone chemotherapy but relapsed quickly. The investigational agent, pralatrexate (30 mg/m2) was given weekly with vitamin B12 and folic acid and resulted in remarkable clinical response with regression of skin tumors. Our observation highlights pralatrexate as a promising therapeutic option for hematodermic/plasmacytoid dendritic cell lymphoma/leukemias.