Sarcoidosis or Tuberculosis ?  That is the question

Summary: Background Sarcoidosis is a multisystem granulomatous disease characterized by noncaseating granulomas in many organs, including the lungs, eyes, skin, and lymph nodes. In contrast, tuberculosis, which is not a common disease in the United States, is characterized by caseating granulomas primarily in the lungs and, in rare cases, the central nervous system, skin, and eyes. However, in rare extreme cases, tuberculosis may present with non-caseating granulomas, making it difficult to differentiate between sarcoidosis and tuberculosis because of their similar clinical presentation. Case presentation A 20-year-old male with a significant past medical history presented to the emergency department with 3 months of progressive epigastric abdominal pain, anorexia, 20 pounda weight loss, night sweats, and wavering fever; patient denied cough, incarceration, or recent travel. The patient was born in Haiti and immigrated to the United States at the age of 15. On admission, heart rate was 89 beats per minute (bpm), respiratory rate was 20 cycles per minute (cpm), and his oxygen saturation was 98% on room air. Physical examination was positive only for mild abdominal distension. CT chest, abdomen revealed mediastinal lymphadenopathy, peritoneal thickening and ascites, extensive lymphadenopathy and periostitis (Figure 1), and erosive changes along the ventral aspect of the L2-L4 vertebral bodies, raising concerns of osteomyelitis, which prompted an MRI. Thoracolumbar MRI showed marrow edema and enhancement of the L2 and L3 vertebral bodies, left paravertebral phlegmonous changes at the L2 level with subcentimeter abscess formation in the left prevertebral soft tissues (Figure 2). Sputum samples were negative for acid-fast bacilli and Quantiferon Tb plus was indeterminate. Peritoneal lymph node and L3/L4 lumbar biopsy were consistent with a noncaseating granuloma. Rheumatologic work-up showed antinuclear antibodies (ANA): 1/40, ESR 120 mm/h, RF negative. Because of a persistent negative workup for TB but high clinical suspicion due to endemic origin, the patient underwent fibrobronchoscopy with bronchoalveolar lavage and paracentesis, which were nondiagnostic for TB. After a negative TB workup, the decision was made to treat empirically with RIPE therapy while awaiting BAL, peritoneal fluid and biopsy cultures. After 2 weeks, cultures from BAL, peritoneal fluid and biopsy came back positive for Mycobacterium tuberculosis. Patient was discharged on RIPE therapy with marked improvement of abdominal symptoms and also on imaging. Discussion: Pulmonary sarcoidosis is a granulomatous disease of unknown etiology that is difficult to diagnose. In patients coming from endemic areas of TB. It is imperative to rule out tuberculosis (TB) as both pathologies have similar clinical, imaging and histologic characteristics. Laboratory and microbiologic tests such as sputum AFB, cultures for TB, biopsies if needed, and other inflammatory markers should be ordered to completely rule out TB or sarcoidosis. This case highlights the importance of a thorough history and laboratory evaluation and the need for a therapeutic trial of RIPE even in patients in whom the pathology is consistent with non-caseating granulomas. Cultures for TB should be ordered from biopsies or BAL if sputum AFB are negative. In our case, sarcoidosis was one of the main differential diagnoses due to the noncaseating granulomas, but epidemiologic history and clinical presentation should be prioritized when making the decision to treat empirically for TB despite pathology. In addition, the administration of steroids for sarcoidosis may have exacerbated TB. It has been previously described that TB can present as non-caseating granulomas in immunocompromised hosts. Our patient was a young, immunocompetent male, which makes our case presentation unique and adds to the medical literature. Conclusions Our case highlights the importance of ruling out TB before starting treatment for sarcoidosis. Non-caseating granulomas are also present in rare cases of TB. Empiric treatment for TB should be based on epidemiologic and clinical presentation. Acknowledgements We thank Dr. Cecilia Chung and all members of the team for making this abstract possible.