Introduction: Paraneoplastic pemphigus is an autoimmune bullous and erosive mucocutaneous syndrome associated with malignancy. First of all, it is associated with lymphoproliferative disorders, but also with solid tumors.

Case report: We present a 73-year-old female patient who developed polymorphic lesions on the skin and mucous membranes after treatment of nonHodgkin's lymphoma. Disseminated pale erythematous macules, exudative papules and plaques, papulovesicles, pustules, targetoid lesions and bullae are present on the skin, mostly with a flaccid roof, some with a hypopyon. Oral mucosal changes included erosions and ulcerations covered by fibrin deposits. Histopathological examination of several biopsies revealed the presence of interface dermatitis, eosinophils, necrotic keratinocytes, as well as intraepidermal cracks with acantholytic cells, dominated by eosinophils. Direct immunofluorescence microscopy of the perilesional skin showed fluorescent intraepidermal reticular IgG deposits, as well as segmental linear IgG deposits along the basement membrane zone. Indirect immunofluorescence microscopy revealed circulating IgG autoantibodies binding to monkey esophagus and rat bladder at a titer of 1:320. Initially, he was treated with systemic corticosteroid therapy, then, in consultation with a hematologist, rituximab therapy was indicated (375 mg/m2, 4 doses once a week). The patient died after the 2nd dose of rituximab.

Conclusion: Considering the different clinical, histopathological and immunological features, paraneoplastic pemphigus presents a challenge for the clinician. Knowledge of different clinical presentations, as well as individualization of therapy with a multidisciplinary approach, are of crucial importance.