Cutaneous CD56 positive natural killer and cytotoxic T-cell lymphomas

We report two cases of CD56 positive natural killer (NK) cell and cytotoxic T-cell cutaneous lymphomas and review the literature on these rare forms of non-Hodgkin's lymphoma. The first case was diagnosed to have extra nodal NK/T-cell lymphoma, nasal-type. She had a rapid downhill clinical course and died within 3 months of presentation. She had been started on systemic chemotherapy but did not respond. The second case was diagnosed as subcutaneous panniculitis-like T-cell lymphoma, CD56 positive variant. She presented with skin nodules that were quiescent for 10 years. Then the course of the disease suddenly changed and progressed rapidly. She had systemic chemotherapy and initially had a complete response, but she relapsed within 1 month of completion of chemotherapy. She then had partial response with further chemotherapy but relapsed rapidly. She died within 15 months of her lymphoma changing to its aggressive form. These cases illustrate the often poor prognosis of cutaneous CD56 positive lymphomas.