Pagetoid reticulosis positive for cytotoxic CD20 and CD30: A case report

Pagetoid reticulosis is an indolent cutaneous T-cell lymphoma and presents as erythema or plaque with a well-defined border on the distal areas of the extremities. Immunophenotypic studies show that in most cases, neoplastic lymphocytes are positive for CD4, whereas CD20 and CD30 double positivity was rarely reported. In this paper, we report an 80-year-old woman who presented with erythema on the extremities for 3 years. Skin biopsy on the right forearm was performed. Histopathologically, the erythematous lesions were characterized by atypical lymphocytes with significant epidermotropism. Immunohistochemical staining showed high proliferation as evidenced by high Ki-67 index and that the tumor cells were positive for CD20 and CD30 but negative for CD7 and CD56. The patient was treated with one cycle of radiotherapy and is currently doing well.