Role of FNAC in diagnosing chronic sialadenitis with rare etiologies: a report of two cases with serological and microbiological correlation

Abstract Background Chronic sialadenitis presents a diagnostic challenge due to its varied clinical manifestations and overlap with infectious and neoplastic conditions. Accurate differentiation between autoimmune and granulomatous causes is crucial, yet often difficult based on clinical and imaging findings alone. Reporting these cases highlights the pivotal role of cytology combined with supportive investigations in reaching definitive diagnoses. Case presentation We describe two female patients presenting with painless salivary gland swellings and lymphadenopathy. Case 1: A 40-year-old woman, had a firm, non-tender left submandibular swelling with bilateral cervical lymphadenopathy. FNAC revealed lymphoepithelial lesions with mixed inflammatory infiltrate; serological testing showed elevated ANA and anti-SSA/SSB antibodies. A diagnosis of Sjögren’s syndrome–associated lymphoepithelial sialadenitis (LESA) was established. Case 2: A 17-year-old girl, presented with a post-auricular swelling and low-grade fever. FNAC demonstrated salivary gland components mixed with focal epitheloid cell granulomas in necrotic background, and ZN staining confirmed acid-fast bacilli (AFB). CBNAAT testing was positive, confirming tubercular sialadenitis. Both patients were started on respective medical management avoiding surgical intervention. Conclusions These cases highlight the critical role of FNAC, combined with serological and microbiological investigations, in establishing the correct diagnosis of chronic sialadenitis of autoimmune and infective granulomatous etiology. Reporting such cases raises awareness of the clinical and imaging challenges associated with salivary gland lesions and underscores the importance of a systematic diagnostic approach incorporating FNAC.