Pulmonary Mycobacterium avium complex infection

Diagnosis certain


Pleuritic right chest pain, worsening exertional dyspnea. Past history of MAC infection.

Patient Data

Age: 65
Gender: Female

Multiple areas of airspace opacities with some confluence foci suspicious for mass lesions on the right as well as right apical changes. 

The pulmonary arteries opacify normally without filling defects to a subsegmental level. There has been progression of the bilateral lung scarring, consolidation and bronchiectasis. There is increased cavitation primarily in the right apical region. Some of the opacity within the left lung is ground glass in appearance. Mediastinal lymph nodes are prominent in number but not size. No pleural effusion. Within the limitations of this study, the visualized upper abdominal viscera are unremarkable.No destructive osseous lesion.


No pulmonary emboli detected. There has been progression of the bilateral lung scarring, consolidation, cavitation and bronchiectasis consistent with history of MAC infection.

Sputum sample

Auramine-Rhodamine Stain:             +++ (> 10 Acid fast bacilli DETECTED per HPF).
Ziehl-Neelsen Stain:                           +++ (> 10 Acid fast bacilli DETECTED per HPF).

MPT64 Antigen Identification Test: M.tuberculosis Complex NOT detected.

M.tuberculosis Complex PCR by GeneXpert: NOT Detected.

MGIT bottle (2 days): POSITIVE.

1.Mycobacterium avium Complex           ISOLATED

Case Discussion

Changes in the right upper lobe are those of old TB with no evidence to suggest reactivation. The significant finding is the multiple lung nodules, some cavitating, with some bronchiectasis. These findings alone do not conclusively prove MAC, however in an elderly patient with the appropriate clinical presentation, (e.g. SOB over months, fevers and usually weight loss) then a radiologist can be confident that the diagnosis is MAC. 

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