Abstract

Lymphomatoid papulosis (LyP) falls under the designation of a primary cutaneous lymphoproliferative disorder which is histologically hallmarked by atypical CD30-positive T-cells. Classically understood as multiple crops of recurrent and self-resolving papules, LyP may also present as a solitary lesion. Here we present the case of a 65-year-old woman with an ulcerated papule on her left ventral forearm. This was biopsied and showed an atypical and tumefactive CD30-positive lymphocytic infiltrate that was originally interpreted as mycosis fungoides (MF) with large cell transformation. The patient was treated with radiation, and the lesion regressed. The lesion later recurred at the same site as a crusty, keratotic patch. Another biopsy showed similar findings: a tumefactive growth of highly atypical lymphocytic infiltrate with malignant-appearing large cells within the dermis. Immunohistochemical workup demonstrated staining for CD8 and CD30, while showing loss of CD4, CD5 and CD7. A diagnosis of unilesional LyP was rendered at this time. The lesion followed the appropriate clinical course and regressed without intervention. Unilesional lymphomatoid papulosis is a rare, indolent and self-resolving lymphoproliferative disorder whose cytologic atypia may cause misdiagnosis as cutaneous T-cell lymphoma.

Financial Disclosure:
No current or relevant financial relationships exist.