C68-15 When Nodules Deceive: A Case of Mycobacterium Chelonae Mimicking Metastases

Introduction Nontuberculous mycobacterium (NTM) infections are becoming more common in immunocompetent individuals. Mycobacterium chelonae is a rapidly growing NTM that rarely causes pulmonary infections and therefore continues to be difficult to diagnose and recognize. Our case demonstrates a unique presentation and computed tomography (CT) scan that is unusual for a Mycobacterium chelonae pulmonary infection. Case Description A 57-year-old male who is a current smoker with no other medical history presented for multiple episodes of hemoptysis. Social and family history was also significant for his 52-pack-year smoking history, and his father dying from lung cancer. Occupational history was significant for work in construction management. His CT of the chest showed bilateral, irregular pulmonary nodules suspicious for metastatic disease, hilar lymphadenopathy, and mediastinal lymphadenopathy. The largest nodule measured 2.1cm x 1.8cm. Our patient underwent endobronchial ultrasound (EBUS) bronchoscopy with transbronchial biopsies, transbronchial needle aspiration of selected lymph nodes, and bronchoalveolar lavage (BAL) of selected areas. Our patient was discharged with appropriate follow-up, and pathology showed necro-inflammatory debris with cytology negative for malignancy. Microbiology results later tested positive for Mycobacterium chelonae growth in the BAL sample from the left upper lobe (LUL). Streptococcus mitis from broth and Staphylococcus epidermidis were isolated from two other tissue samples as well. Our patient was readmitted to the hospital for continued episodes of hemoptysis, fevers, and leukocytosis. This hospital course was complicated by an empyema that required treatment with a chest tube, atrial fibrillation with rapid ventricular response (RVR) that required a diltiazem infusion followed by a transesophageal echo (TEE) with cardioversion, and broad spectrum antibiotics. Our patient’s clinical status improved, and he was ultimately transitioned to IV tobramycin for six weeks, PO azithromycin, and PO trimethoprim-sulfamethoxazole (TMP-SMX) at discharge. He was also given a flutter valve for pulmonary hygiene. After completion of the tobramycin, final susceptibilities resulted for the Mycobacterium chelonae, and TMP-SMX was switched to linezolid. Our patient continues to regularly follow with infectious disease specialists for treatment of his NTM infection. Discussion Mycobacterium chelonae is more commonly seen in skin and soft tissue infections and is rarely accounted for causing pulmonary infections. When it does cause a pulmonary infection, CT scans often demonstrate subcentimeter nodules, bronchiectasis, and consolidations. Our patient’s initial CT scan was more consistent with a metastatic neoplastic pattern, which made the diagnosis and ultimate management unique. This abstract is funded by: None