B57-15 Not All Granulomas Are Sarcoid: Environmental Pneumoconiosis Mimicking Sarcoidosis in an Asymptomatic Patient

Abstract Introduction Sarcoidosis is a multisystem granulomatous disease characterized by non-caseating granulomas and bilateral hilar lymphadenopathy. However, environmental pneumoconiosis may closely resemble sarcoidosis radiologically and histologically, creating a diagnostic dilemma. Distinguishing between these entities is essential to avoid unnecessary corticosteroid therapy in patients with exposure-related granulomatous disease. Case Report A 66-year-old retired male presented for a routine primary-care visit and was entirely asymptomatic. His medical history included treated hepatitis B and C and a forty-year history of cigarette smoking. Chest computed tomography (CT) revealed multiple bilateral 2-8 mm centrilobular nodules and calcified mediastinal and hilar lymphadenopathy. Bronchoscopy with endoscopic ultrasound (EUS)-guided lymph node biopsy demonstrated non-caseating epithelioid granulomas. Stains and cultures for acid-fast bacilli (AFB) and fungi were negative, and pulmonary function testing (PFT) was normal.Further evaluation uncovered a detailed occupational history of forty-nine years of installing awnings, with daily exposure to fiberglass, metal dust, and insulation materials, ending six months prior to presentation. No systemic features, extrapulmonary involvement, or autoimmune history were identified. Based on clinical, radiologic, and pathologic correlation, a diagnosis of environmental pneumoconiosis mimicking sarcoidosis was established. The patient remained asymptomatic and was managed conservatively with exposure avoidance, pneumococcal vaccination, and serial imaging surveillance Discussion This case highlights the diagnostic challenge when radiologic and histopathologic findings overlap between sarcoidosis and occupational pneumoconiosis. Non-caseating granulomas and bilateral hilar lymphadenopathy do not always indicate sarcoidosis. Chronic exposure to fiberglass and metal dust can produce a sarcoid-like pattern both radiologically and histologically. A meticulous occupational history is critical for diagnostic accuracy and prevents unnecessary immunosuppressive treatment. This case underscores the importance of environmental and occupational evaluation in patients with granulomatous lung disease, particularly in asymptomatic individuals. Awareness of such sarcoid-like pneumoconiosis expands the understanding of non-infectious, non-autoimmune causes of granulomatous inflammation and reinforces the need for careful history-taking before initiating treatment. This abstract is funded by: None