Talimogene laherparepvec (TVEC) pseudolymphomatous reaction mimicking metastatic melanoma.

Henning, Ania; Agnese, Doreen; Chung, Catherine G

Talimogene laherparepvec (TVEC) is a genetically modified herpes simplex virus-1 approved as an intralesional oncolytic immunotherapy for the treatment of advanced melanoma. Cutaneous reactions at the site of injection may mimic recurrent or progressive melanoma; histopathological findings have included chronic granulomatous dermatitis, neutrophilic dermatitis, lymphocytic dermatitis and pigment incontinence. We report a 39-year-old male with metastatic stage IIIc melanoma treated with TVEC with clinical regression of melanoma lesions that later developed pink nodules at sites of prior injection. Histopathology demonstrated a nodular mononuclear infiltrate that stained strongly and diffusely with CD45 and CD20 with a surrounding rim of CD3-positive T-cells. Immunoglobulin gene rearrangement was negative for a clonal B cell population. To our knowledge, this is the first report of a pseudolymphomatous reaction mimicking recurrent melanoma after TVEC therapy. This article is protected by copyright. All rights reserved.