Paraneoplastic Pemphigus Revealing Synchronous Pulmonary and Gastric Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma: A Rare Case Report

Abstract

Aims: To describe a rare case of paraneoplastic pemphigus (PNP) occurring in a patient with synchronous pulmonary and gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to summarise the diagnostic and therapeutic considerations documented in this case. Presentation of Case: A 71-year-old man with recently diagnosed synchronous pulmonary and gastric MALT lymphoma developed a rapidly progressive polymorphic blistering eruption. Four days later, severe erosive stomatitis developed and extended to the genital and conjunctival mucosae. A skin biopsy demonstrated suprabasal intraepidermal acantholysis with epidermal acanthosis and scattered eosinophilic inflammatory cells. Direct immunofluorescence showed intercellular IgG deposition, while indirect immunological testing identified high-titre circulating anti-intercellular substance antibodies (1:640); anti-basement membrane antibodies were negative. On the basis of the clinical, histopathological, immunopathological, and oncological findings, PNP was diagnosed after multidisciplinary assessment. Systemic corticosteroid therapy was initiated, followed by R-CHOP chemotherapy for the underlying lymphoma. Despite combined immunosuppressive and oncological treatment, the patient developed profound febrile neutropenia and overwhelming sepsis two days after the second chemotherapy cycle and died despite intensive supportive management. Conclusion: This case illustrates the severe clinical course that PNP may have in association with an indolent B-cell lymphoma and emphasises the importance of early recognition, malignancy assessment, and multidisciplinary management when polymorphic blistering and progressive mucosal disease occur.