대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Nontuberculous mycobacterial pulmonary disease

Radiologic Findings

Fig 1. High-resolution CT image shows a about 1.5 cm cavitary nodule in right upper lobe.
Fig 2. The lesion shows increased size on follow-up CT after 4 months.
Fig 3. The lesion shows further size increase on follow-up CT after 2 months.
Fig 4. On axial contrast-enhanced CT, the lesion shows poor peripheral enhancement (Hounsfield unit: 38).
Fig 5. Chest radiograph shows a 2.8 cm cavitary nodule in right upper lung field.

Surgical excision was performed. The histological diagnosis was chronic granulomatous inflammation, while NTM PCR was positive.

Brief Review

The most common cause of benign solitary pulmonary nodules is mycobacterium tuberculosis, but recent advances in microbiologic diagnosis have led to increased confirmation of solitary pulmonary nodules due to NTM disease. Hong et al. have reported that the incidence of NTM pulmonary disease mimicking lung cancer clinically and radiologically was 3.6% (14 of 388). Typical imaging features of NTM disease are cellular bronchiolitis with or without bronchiectasis (i.e., nodular bronchiectatic form) or cavitary lesions with upper lung predominance (i.e., upper-lobe cavitary form). However, NTM pulmonary disease can also manifest as an SPN, solitary mass, or mass-like consolidation. These lesions usually present with radiologic features overlapping those of primary lung cancer. In contrast to primary lung cancer, NTM pulmonary disease typically shows poor contrast enhancement and frequent internal calcification on CT. FDG PET/CT does not provide additional information to help differentiation from lung cancer, because NTM disease can cause false-positive results including other chronic inflammatory diseases such as tuberculosis, fungal infection, and sarcoidosis. Considering the increasing prevalence of NTM disease worldwide, NTM disease should be included as one of the differential diagnoses of an SPN, mass, or mass-like consolidation in clinical practice.

Please refer to

Case 88, Case 243, Case 566,

KSTR Imaging Conference 2005 Spring  Case 6 ,
KSTR Imaging Conference 2007 Spring  Case 12,

References

1. SJ Hong, TJ Kim, JH Lee, JS Park, Nontuberculous mycobacterial pulmonary disease mimicking lung cancer. Medicine (2016) 95:26(e3978)

Keywords

lung, bacterial infection, nontuberculous mycobacterial Infection,