P297: A case of primary cutaneous CD4 positive small/medium-sized pleomorphic T cell lymphoma

Primary cutaneous CD4 positive small/medium T cell lymphoma (PCSM-TCL) represents a provisional subtype of primary cutaneous T-cell lymphoma with indolent clinical course. PCSM-TCL is a rare disease representing approximately 2% of all primary cutaneous T-cell lymphomas. It is clinically characterized by a solitary or several nodules, plaque, or tumor and usually involving the head and neck. Histologically, PCSM-TCL is characterized by a dense infiltration of small/medium sized pleomorphic T cells. Clonal T cell receptor gene rearrangement has been detected in most cases. Immunohistochemically, CD3 and CD4 are positive, but CD8 and CD30 are negative in the majority of the case. A 65-year-old man presented with 5cm sized solitary erythematous plaque on left upper eyelid for 2 months. Histologically, the specimen from left upper eyelid showed infiltration of small/medium sized pleomorphic atypical lymphocytes and a few eosinophils. Immunohistochemical study revealed positive of CD3 and CD4 but negative of CD8, CD20, CD56, Granzyme B. Further evaluation for systemic involvement including computed tomography, magnetic resonance imaging and bone marrow biopsy were done at other tertiary center, there was no tissue confirmation of metastatic lesions, skin lesion. The patient has not recurred since total excision of the lesion. Here, we report a case of PCSM-TCL.