From sicca to malignant evolution: a swift turn to multiple myeloma in primary Sjögren’s syndrome

Abstract

Primary Sjögren’s syndrome (pSS) is a chronic autoimmune disorder characterized by exocrine gland involvement and systemic B cell hyperactivity. Although hematologic complications are recognized, transformation to multiple myeloma (MM) remains exceptionally uncommon. We report a 50-year-old woman who presented with constitutional symptoms, sicca manifestations and recurrent vasculitic skin lesions. Evaluation established a diagnosis of primary Sjögren’s syndrome with associated monoclonal gammopathy of undetermined significance (MGUS). Despite initial management and follow up, she subsequently developed worsening systemic symptoms accompanied by progressive extra glandular manifestations, prompting reassessment. Serial investigations confirmed progression to multiple myeloma within a relatively short interval. The patient was managed collaboratively by rheumatology and hematology departments and showed favorable clinical and laboratory response to therapy. This case highlights a rare malignant evolution in pSS and underscores the importance of maintaining a high index of suspicion in patients with persistent systemic symptoms, paraproteinemia, vasculitic manifestations or unexplained clinical deterioration. Careful longitudinal monitoring may facilitate earlier recognition of hematologic transformation and enable timely therapeutic intervention, potentially improving patient outcomes.