Long‐term follow‐up and management of small and medium‐sized CD 4 + T cell lymphoma and CD 8 + lymphoid proliferations of acral sites: a multicenter experience

Background Primary cutaneous CD 4 + small–medium pleomorphic T cell lymphoma ( SMPTCL ) is a low‐grade cutaneous T cell lymphoma. Its clinical and histopathologic features are comparable with those of CD 8 + lymphoid proliferations ( LP s) of the ear and acral sites. Objectives We performed a retrospective analysis of patients with CD 4 + SMPTCL or CD 8 + LP to elucidate the clinical course, prognosis, and outcomes. Methods Demographic, clinical, and treatment data were reviewed. Histopathologic data based on architectural, cytomorphologic, and immunohistochemical features were assessed. Immunohistochemical staining for T and B cell markers was evaluated. Results A total of 25 patients including 22 with CD 4 + SMPTCL and three with CD 8 + LP were identified. All patients presented with a single lesion, predominantly on the head, neck, or upper trunk (84%). No patients showed extracutaneous disease at any evaluation. The most common histopathologic changes showed a dense nodular infiltrate of small cells with hyperchromatic nuclei without significant follicular or adnexal involvement. Patients were treated with excision (48%), local radiation (28%), or topical or intralesional steroids (24%). All patients achieved complete resolution of disease. Five patients demonstrated cutaneous relapse at new sites. Conclusions The CD 4 + SMPTCL / CD 8 + LP subgroup usually presents with solitary lesions and demonstrates an indolent clinical course. Typical presentation, classic histopathology, widespread expression of follicular T helper cell markers, and loss of a T cell antigen are diagnostic features of CD 4 + SMPTCL , whereas monomorphous CD 8 + infiltrate without follicular T helper cell markers is consistent with CD 8 + LP . Local skin‐directed therapy is appropriate in these patients.