Extranodal NK/T-cell lymphoma primarily presenting as two adjacent slowly growing skin nodules with prominent epidermotropism and CD30 expression, a case report and review of literature.

ABSTRACT

Extranodal NK/T-cell lymphoma (NKTCL) is a rarely occurring non-Hodgkin lymphoma with predilection for the nasal cavity. Cutaneous involvement, rarely occurring and often aggressive in behavior, may present as nodular mass-forming lesions with or without ulceration. Histologically, lesions are characterized by an atypical dermal lymphoid infiltrate with angioinvasion and associated necrosis. Fortuitously, Epstein-Barr virus (EBV) infection, implicated in the pathogenesis of this entity, serves as a useful diagnostic marker (i.e. EBER in situ hybridization). We present a 54-year-old-man who initially presented with two ulcerations on the right lower leg which progressed despite antibiotic therapy. Histologic examination demonstrated dense lymphoid infiltrates exhibiting epidermotropism, angiocentricity and angioinvasion extending into the deep dermis. Immunohistochemical staining demonstrated expression of CD2, CD3, CD8, TIA-1, perforin, and granzyme-B, consistent with a cytotoxic T-cell phenotype. Additionally, CD56 was positive, confirming the presence of a coexistent NK cell phenotype. Testing also demonstrated significant CD30 expression, and molecular analysis was positive for TCR gene rearrangement. These findings, in conjunction with EBER in situ hybridization positivity, confirmed a diagnosis of extranodal NKTCL. We aim to increase awareness of this rarely occurring lymphoma with cutaneous involvement. CD30 expression in NKTCL raises the possibility of targeted treatment with brentuximab.