title: Cutaneous B-cell lymphoma with histologic features of mycosis fungoides.
abstract: Histologic examination of skin biopsy specimens from a 57-year-old man with a pruritic rash on his chest, abdomen, and thighs revealed a dense atypical dermal lymphoid infiltrate bordering the dermoepidermal junction and scattered intraepithelial lymphocytes. Histopathologic and clinical features were suggestive of mycosis fungoides. Immunophenotyping studies, however, identified CD20(+) B lymphocytes with aberrant expression of CD43. Clonal immunoglobulin gene rearrangement was demonstrated, and no clonal T-cell gene rearrangement was identified. Morphologic and immunophenotypic features were most consistent with extranodal marginal zone B-cell lymphoma. Systemic evaluation identified involvement of the bone marrow and possibly the peripheral blood, spleen, and splenic lymph nodes. Cutaneous manifestations were treated with narrowband ultraviolet B phototherapy for 3 months, resulting in complete resolution of the pruritus and rash. Primary and secondary cutaneous B-cell lymphomas seldom mimic mycosis fungoides histologically. Immunophenotyping studies were critical in correctly classifying this rare example of an epidermotropic B-cell lymphoma.
authors.affiliation: Department of Dermatology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Chiang
authors.forename: David J
authors.initials: DJ
authors.lastname: DiCaudo
authors.forename: Riccardo
authors.initials: R
authors.lastname: Valdez
authors.forename: David L
authors.initials: DL
authors.lastname: Swanson
mesh_terms: D001402:B-Lymphocytes / Q000528:radiation effects; D003937:Diagnosis, Differential; D006801:Humans; D016393:Lymphoma, B-Cell / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy; D008297:Male; D009182:Mycosis Fungoides / Q000175:diagnosis / Q000473:pathology*; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy; D014467:Ultraviolet Therapy