A Case of Primary Cutaneous CD4+ Small/Medium T-cell Lymphoproliferative Disorder

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (PCSM-TCLPD) is a rare lymphoproliferative condition that typically manifests as a solitary, asymptomatic cutaneous nodule. Systemic involvement is uncommon, and diagnosis is confirmed via biopsy, which reveals a predominant population of CD4-positive T-cells with a follicular helper T-cell phenotype. Treatment generally involves conservative local approaches, including biopsy, topical steroids, or excision, with many cases demonstrating spontaneous regression after biopsy. This report presents the case of a 68-year-old woman with a 6.0 x 6.0 mm subcutaneous nodule on the left preauricular cheek. The lesion appeared over 4–5 weeks and was asymptomatic. Biopsy revealed a dense lymphohistiocytic infiltrate of predominantly CD4-positive T-cells, with clonality confirmed through molecular studies. Additional workup, including complete blood count, metabolic panel, and imaging, revealed no systemic involvement. Oncology recommended observation without further excision. At three months post-biopsy, the lesion had not recurred. PCSM-TCLPD, which accounts for 5% of primary cutaneous lymphomas, was reclassified as a lymphoproliferative disorder by the World Health Organization in 2016 due to its indolent nature. While its prognosis is excellent, with a five-year survival rate near 100%, careful diagnostic and therapeutic strategies are critical. Spontaneous remission post-biopsy supports the role of conservative management, minimizing invasive interventions. This case underscores the importance of recognizing PCSM-TCLPD’s clinical and histopathological features to ensure accurate diagnosis and optimize patient outcomes while avoiding unnecessary procedures. Further research is needed to refine treatment and follow-up strategies for this rare condition.