A Case of Mycobacterium Avium Complex Masquerading as a Lung Mass in a Lung Transplant Recipient

SESSION TITLE: Transplantation SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Lung transplant recipients have an increased risk of non-tuberculous mycobacterial infections, most frequently presenting with pleuropulmonary disease. Discussed here is an uncommon manifestation of MAC in a lung transplant recipient. CASE PRESENTATION: A 70 year old man with a history of bilateral orthotopic lung transplant for COPD 5 years prior presented with abnormal chest imaging and a decline in PFTs. His course had been complicated by early PTLD, rejection, and immunosuppression attenuation due to skin cancers. Recent bronchoscopy revealed 1 colony of acid-fast bacilli (AFB) and no rejection. CT imaging showed a growing right lower lobe mass that was not PET avid (Figure 1A). Transbronchial biopsy cytology was AFB positive and pathology demonstrated inflammation. Flow cytometry and stains for other infections were negative. A transthoracic biopsy revealed organizing pneumonia and non-necrotizing granulomas (Figure 1B). Triple therapy for mycobacterium avium complex (MAC) was started and follow-up imaging showed a decrease in mass size. DISCUSSION: Non-tuberculous mycobacteria (NTM) are common findings following lung transplantation, isolated in 0.46-8% of recipients; however only a minority meet criteria for treatment. Guidelines recognize compatible radiographic features of NTM as fibrocavitary or nodular/bronchiectatic. Compared with immunocompetent hosts, non-HIV immunocompromised hosts more frequently present with masses (>2cm), although fibrocavitary and bronchiectatic patterns are the most frequently encountered radiographic features. Masses are frequently mistaken for malignancy. NTM disease is associated with declines in pulmonary function in lung transplant patients. CONCLUSIONS: This case represents an uncommon radiographic presentation of NTM infection in a lung transplant recipient that was concerning for recurrence of malignancy. NTM is protean in nature on radiographs and in this case required repeated biopsies to more definitively rule out cancer in a suspicious lesion. Reference #1: Lee,Y. et al. CT findings of pulmonary non-tuberculous mycobacterial infection in non-AIDS immunocompromised patients: a case-controlled comparison with immunocompetent patients. Br J Radiol 86, (2013). Reference #2: Knoll,B.M. et al. Non-tuberculous mycobacterial infection among lung transplant recipients: a 15-year cohort study. Transpl Infect Dis 14, 452-460 (2012). Reference #3: Keating,MR, et al. Nontuberculous Mycobacterial Infections in Solid Organ Transplantation. Am Journal of Transplantation 13, 77-82 (2013). DISCLOSURE: The following authors have nothing to disclose: Joshua Smith, Clausen Emily, Edward Kessler, Kamran Mahmood, Scott Shofer, Momen Wahidi, George Cheng No Product/Research Disclosure Information