SESSION TYPE: Infectious Disease Cases II
PRESENTED ON: Tuesday, October 23, 2012 at 11:15 AM - 12:30 PM
INTRODUCTION: It is often difficult to discern true mycobacterial infection from colonization due to Mycobacterium gordonae .It can be a rare cause of significant pulmonary infection. Positive sputum or BAL cultures should not be automatically discarded especially in immunocompromised hosts with comorbidities.
CASE PRESENTATION: A 54 year old white male former plumber was referred for infectious diseases and pulmonary evaluation because of weight loss, worsening cough productive of grayish white sputum, night sweats, and newly noted mediastinal adenopathy. He had a history of COPD, and disabling rheumatoid arthritis for which he was on prednisone and methotrexate. Computed tomography scan of the chest showed mediastinal adenopathy in the pretracheal and subcarinal regions, measuring 2.1 x 1.5 cm, and 1.4 x 3.5 cm respectively with concomitant insterstitial infiltration and honey-combing of both lungs.He underwent bronchoscopy and mediastinal lymph node biopsy by video assisted thoracoscopic surgery. Pathologic exam of the resected lymph node showed caseating granulomatous inflammation and well defined suppurative necrotic centers surrounded by palisading epithelioid macrophages. Mycobacterial cultures of the resected caseating granulomatous lymph node tissue and bronchoalveolar lavage both grew a mycobacterium identified as Mycobacterium gordonae.
DISCUSSION: Caseating mediastinal lymphadenitis with concomitant lung disease caused by Mycobacterium gordonae infection has not been reported before.Positive clinical cultures for this organism should be carefully reviewed. Diagnosis should be based on the presence of pulmonary symptoms with appropriate exclusion of other etiologies in addition to radiologic and microbiologic evidence of disease caused by nontuberculous mycobacteria. Radiologic evidence of disease includes nodular or cavitary opacities on chest radiograph or a high resolution CT scan. Microbiologic confirmation involves positive culture results from at least two separate expectorated sputum samples, positive culture results from at least one bronchial wash or lavage, or transbronchial or other lung biopsy with mycobacterial histopathologic features and positive culture for nontuberculous mycobacteria or biopsy showing mycobacterial histopathologic features and one or more sputum or bronchial washings that are culture positive for nontuberculous mycobacteria.
CONCLUSIONS: Invasive lung disease due to Mycobacterium gordonae may occur especially in immunocompromised patients.When isolates of this pathogen grow in clinical cultures, they should not be automatically discarded as contaminants.Mycobacterium gordonae can cause caseating mediatinal lymphadenitis mimicking Mycobacterium tuberculosis in an immunocompromised host.
1) Eckburg PB, Buadu EO, Stark P, Sarinas PS, Chitkara RK, Kuschner WG: Clinical and chest radiographic findings among persons with sputum culture positive for Mycobacterium gordonae: a review of 19 cases. Chest 2000; 117:96-102.
DISCLOSURE: The following authors have nothing to disclose: Adel El Abbassi, Wael Shams, Jonathan Moorman, Yasmin Elshenawy, Dima Youssef
No Product/Research Disclosure InformationEast Tennessee State University, James H. Quillen College of Medicine, Johnson City, TN