Erythema multiforme-like lesions in primary cutaneous aggressive cytotoxic epidermotropic CD8+ T-cell lymphoma: A diagnostic and therapeutic challenge.

Primary cutaneous aggressive cytotoxic epidermotropic CD8+ T-cell lymphoma is an extremely rare, rapidly progressing, cutaneous lymphoma, with frequent systemic involvement and poor prognosis, that still represents a diagnostic and therapeutic challenge, especially in the early stage. Herein, we report a case of an elderly woman with a fulminant course, who at onset presented with clinical and pathological features mimicking erythema multiforme (EM) and treated with cyclosporine that led to rapid deterioration with fatal outcome 6 months after disease onset. Histopathology showed a lichenoid, epidermotropic and nodular, angiocentric, dermal and subcutaneous infiltrate of sF1, CD8+, CD45RA+ small to medium-sized atypical lymphoid cells, which strongly expressed cytotoxic markers. Monoclonal T-cell-γ receptor was clonally rearranged and array-CGH showed numerous chromosomal imbalances. This case evidences the clinical, pathological and therapeutic challenges involved in this tumor. The first biopsy showed an interface dermatitis-like pattern, revealing the deceptive features that early cutaneous infiltrates of this aggressive lymphoma may have. A high suspicion for aggressive CTCL and a low threshold for repeat biopsies should be maintained when faced with rapidly progressing and/or ulcerative EM-like lesions, especially if immunomodulatory therapy is being considered.