Abstract

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (PCSMLPD) is an indolent follicular T-helper cell disorder confined to the skin. Most cases affect individuals in the sixth to seventh decades with less than 10 pediatric cases reported in the literature. Originally described as a lymphoma, PCSMLPD was provisionally reclassified from to a lymphoproliferative disorder in 2016 by the World Health Organization due to its indolent nature. The five year survival rates are reported up to 100% for limited disease. Serial examination with lymph node evaluation and complete blood count with differential is recommended. Here we report a rare pediatric case of PCSMLPD. An 8-year-old male presented with asymptomatic 1.5 cm erythematous plaque on the right temple present for 8 weeks. The differential diagnosis included juvenile xanthogranuloma, solitary mastocytoma, and pseudolymphoma. A punch biopsy was initially concerning for Langerhans cell histiocytosis, but was determined to be an atypical lymphocytic infiltrate. Further immunohistochemical evaluation revealed a T-cell proliferation with mostly CD3+ T cells, more CD4+ than CD8+ cells, and positive PD1 in a pseudo-rosette pattern. The lesion was negative for CD30, p53, and TdT. No epidermotropism was present. Based upon these findings and clinical correlation, a diagnosis of PCSMLPD was made. A decision for observation and close monitoring was made with the family. The patient was referred to pediatric oncology. Recognition of PCSMLPD is important for both the clinician and pathologist. PCSMLPD must be differentiated from mycosis fungoides and other cutaneous lymphoma. In this case, recognition of PCSMLPD likely spared this child an unnecessary bone marrow biopsy. The presence of constitutional symptoms and/or significant lymphadenopathy, however, should prompt the clinician to consider other diagnoses.

Financial Disclosure:
No current or relevant financial relationships exist.