Cutaneous involvement as a rare first sign of systemic mantle cell lymphoma: A case report and review of the literature.

Mantle cell lymphoma (MCL) is a unique type of B-cell non-Hodgkin's lymphoma, which very rarely exhibits skin involvement. We herein describe the case of a 55-year-old woman, who initially presented with a nodular mass of the right infraorbital region. On histological analysis of the subcutaneous tissue, a diffuse neoplastic cell infiltration was identified, composed of medium-sized lymphoid cells with irregular nuclei, which was diagnosed as MCL. The tumor cells were positive for CD5, CD20, CD79a, cyclin D1 and sex-determining region Y-box 11, but negative for CD10 and CD23. Our patient received six cycles of R-CHOP chemotherapy and intrathecal methotrexate as central nervous system prophylaxis. However, the patient relapsed 1 year later and was treated with two cycles of R-DHAP and one cycle of intrathecal methotrexate. After achieving partial remission, the patient was consolidated with peripheral blood stem cell transplantation using the BEAM conditioning regime. While prior case studies suggest that skin invasion by MCL is associated with a poor prognosis, our patient remains alive almost 4 years after the initial presentation. Skin involvement as a first sign of systemic MCL is very rare and must be considered.