摘要:Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder is a rare disease characterized by a single mass on the face or upper part of the trunk. It usually presents an asymptomatic and favorable progression, and its histopathologic findings include small and medium-sized lymphoid cells. The authors report a case of primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder on the forehead. A 51-year-old man presented with a protruding mass on his forehead that the patient had noted 1 month previously. Surgical excision and a permanent biopsy were performed under local anesthesia. Based on the biopsy results, the mass was diagnosed as a primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder. There was no evidence of recurrence at a 15-month follow-up visit.