Simultaneous presentation of bullous pemphigoid and mycosis fungoides

The relationship between bullous pemphigoid (BP) and neoplasms has been debated in the medical literature. Although numerous case reports have described the coexistence of BP with various neoplasms, case-control studies have yielded conflicting results. We present the case of a male patient who developed BP shortly after being diagnosed with mycosis fungoides (MF). He was a 77-year-old man with a history of type 2 diabetes mellitus and hypertension who was diagnosed with MF. Subsequently, he developed blisters after sun exposure, and was diagnosed with BP through histopathology and direct immunofluorescence. The patient was treated with prednisone and methotrexate, with favorable evolution without recurrence of MF or appearance of new blisters. The association between cutaneous T-cell lymphoma and autoimmune blistering disease is rare, although similar cases have been reported, some associated with phototherapy. In this case, the onset of BP after sun exposure suggests a potential connection. The coexistence of BP and MF remains controversial, and this case highlights the importance of considering autoimmune blistering diseases in patients with oncohematological neoplasms.