Primary cutaneous CD4-positive small or medium T-cell lymphoproliferative disorder: a case report and literature review.

Primary cutaneous CD4-positive small or medium T-cell lymphoproliferative disorder (PCSM-LPD) is characterized by a slow-growing and asymptomatic solitary plaque or tumor, usually involving the head, neck, or upper extremities. The diagnosis is established based on clinical presentation, histopathological features including pleomorphic morphology and CD4-positive immunophenotype of neoplastic T lymphocytes, and molecular analysis showing clonally rearranged T-cell receptor (TCR) genes. Plaques typical of mycosis fungoides are essentially absent. Treatment options include surgical excision, radiotherapy, and topical or intralesional steroids. Because the disease is indolent, aggressive diagnostic tests and systemic treatments are not recommended. We present a case of PCSM-LPD in a previously healthy young man that spontaneously regressed after a biopsy.