Bullous mycosis fungoides: Report of a case complicated by Kaposi's varicelliform eruption

Vesiculobullous eruptions in mycosis fungoides (MF) are extremely rare. Here, we report a case of a 62‐year‐old woman presenting with erythematous patches and plaques of 2 years in duration, who had recently developed vesicles on erythematous MF plaques. Histopathological examination showed intra‐subepidermal blisters, and infiltration of the epidermis by atypical lymphoid cells, forming Pautrier's microabscesses. Negative immunofluorescence excluded autoimmune blistering diseases. Immunohistochemistry revealed a CD4+ T‐cell phenotype and gene rearrangement study confirmed a clonal T‐cell proliferation. Kaposi's varicelliform eruption (KVE) developed in the patient 1 week after initiation of systemic corticosteroids and immunotherapy. Cluster of vesicles and erosions arising on the pre‐existing plaque and a positive immunofluorescence test for Herpes simplex virus and histopathological examination confirmed the diagnosis of cutaneous herpes infection. This is the first case report on bullous MF complicated by KVE in the published work.