A Rare Case of Nodal T-follicular Helper Cell Lymphoma That Developed Cutaneous Lesions With Numerous Epstein-Barr Virus-Positive T Cells.

We report a case of nodal T-follicular helper cell lymphoma (TFHL) in an elderly patient who developed multiple cutaneous lesions containing abundant Epstein-Barr virus (EBV)-positive neoplastic T cells. A pharyngeal mass and systemic lymphadenopathy were identified in a 78-year-old male. A histological and immunohistochemical review demonstrated diffuse and nodular infiltrates composed of small- to medium-sized atypical CD3-, CD4- and TFH cell marker-positive lymphoid cells, with scattered EBV-positive B cells and T cells. A diagnosis of nodal TFHL was made, but the patient refused chemotherapy. Indurated erythematous plaques and cutaneous nodules involving the trunk and arms developed one year and eight months after the onset of the lymph node and pharyngeal lesions. A histological examination of the skin nodule demonstrated diffuse infiltration of atypical small- to medium-sized lymphoid cells in the dermis and subcutis. Immunohistochemistry demonstrated that the atypical lymphoid cells were CD3- and CD4-positive and expressed TFH cell markers. Numerous EBV-positive cells were identified among the CD3- and CD4-positive atypical lymphoid cells. Skin lesions of EBV-positive nodal TFHL were diagnosed. The clinical course was aggressive despite chemotherapy, and the patient developed overt leukemic changes and ultimately died of the disease. This is the first reported case of EBV-positive nodal TFHL showing cutaneous lesions demonstrating intense EBV infection in CD3- and CD4-positive lymphoid cells. The presence of EBV- and CD4-positive T cells in the initial biopsy specimens and the subsequent appearance of skin lesions with numerous EBV- and CD4-positive lymphoid cells may indicate accelerated EBV infection and an aggressive phenotypic transformation.