C40-22 The Ultimate Mimic: Diagnostic Challenges in Acute-Onset Sarcoidosis

Abstract Introduction Although sarcoidosis typically follows a chronic course, acute presentations may mimic sepsis, malignancy, or autoimmune disease, posing diagnostic challenges. Sarcoidosis is a multisystem granulomatous inflammatory condition of unknown etiology. Presentation is typically indolent, though acute manifestations can occur. Here, we describe three cases of acute-onset sarcoidosis. Case Presentations 1) 37-year-old male with no prior medical history presented with acute synovitis, myalgias, fever (39.2 °C), and hypoxemia (91% on 2L NC). Skin exam revealed patchy morbilliform erythematous plaques. Chest CT revealed bilateral lower lobe ground glass opacities, interlobular septal thickening, mediastinal adenopathy, and small pleural effusions. Initial differential included sepsis, malignancy, and rheumatologic disease. Infectious and rheumatologic workups were negative. Endobronchial ultrasound (EBUS) with lymph node biopsy revealed non-necrotizing granulomatous lymphadenitis, concerning for sarcoidosis. 2) 34-year-old male with diabetes, decompensated cirrhosis and recurrent thrombotic disease was admitted for severe abdominal pain thought to be secondary to acute splenic thrombosis. PET imaging revealed hypermetabolic mediastinal, hilar, and mesenteric lymphadenopathy. Hypercoagulable evaluation was negative. Given suspicion for malignancy or lymphoproliferative disease, he underwent EBUS. Biopsies of mediastinal, mesenteric and supraclavicular lymph nodes revealed granulomatous inflammation. It was suspected his pro-thrombotic disease was secondary to sarcoidosis. 3) 43-year-old woman with hypertension and aortic regurgitation developed hypoxic respiratory failure after experiencing progressively worsening dyspnea over two weeks. Laboratory workup was notable for hypercalcemia to 12.5 mg/dL (8.4-10.5 mg/dL). Hypoxemia originally was thought to be secondary to aortic regurgitation, however, further imaging revealed diffuse nodular lung consolidations more obvious in the upper lobes, along with mediastinal adenopathy. Work up for worsening aortic regurgitation and infection was unrevealing. She then underwent EBUS with lymph node and transbronchial biopsies. Pathology demonstrated non-necrotizing granulomatous lymphadenitis. Discussion Approximately half of individuals with sarcoidosis are asymptomatic. These cases highlight the diverse and sometimes acute clinical manifestations of the disease. Because presenting features frequently overlap with those of malignancy or autoimmune conditions, establishing the diagnosis can be challenging. In our patients, coexisting conditions further obscured the underlying etiology, necessitating tissue histopathology for diagnostic support. Given the severity of presentation, corticosteroid therapy was initiated promptly, leading to resolution of symptoms. Conclusion Acute-onset sarcoidosis represents an uncommon manifestation of a typically indolent disease. Clinicians should maintain a high index of suspicion for acute sarcoidosis in appropriate clinical contexts, as timely recognition can significantly influence management. This abstract is funded by: none