Relapsing polychondritis in systemic sclerosis: A rare vasculitic mimic.

Introduction: Relapsing polychondritis is a rare, immune-mediated disease characterised by inflammation of cartilaginous structures. Auricular chondritis, sparing the fatty lobule, is the most typical feature, followed by nose and laryngotracheal involvement. Albeit rare, neurologic involvement is reported with relapsing polychondritis. Cranial nerve involvement is the most frequent neurologic manifestation and is probably due to an underlying vasculitic process. Approximately one-third of relapsing polychondritis patients can overlap with other systemic diseases, including other autoimmune connective tissue diseases, but association with systemic sclerosis has very rarely been described. Case description: A 63-year-old woman presented with acute new-onset severe dysphagia, accompanied by hoarseness and preceded by pain, swelling and erythema of the left pinna, unresponsive to antibiotics. She had a history of long-standing limited cutaneous systemic sclerosis. Cranial nerve examination revealed right-sided palatal palsy, and left vocal cord palsy was found on fibreoptic nasendoscopy. Magnetic resonance imaging of the head and neck showed bilateral enhancement of an extracranial segment of the glossopharyngeal and vagus nerves. Clinical features and imaging findings were consistent with relapsing polychondritis, which successfully responded to high-dose steroids. Conclusions: This is a case of relapsing polychondritis mimicking progression of systemic sclerosis, showcasing its challenging features. It emphasises the importance of early diagnosis and prompt management with potential impact on the outcome, while highlighting the complex interplay between these two disease entities and vasculitic mechanisms, which may reflect the shared network of genetic predisposition across autoimmune rheumatic diseases.