Work

Radiographic progression despite microbiologic clearance in pulmonary Mycobacterium avium complex disease revealing concurrent lung adenocarcinomaa

Year: 2026

Type: article

Abstract: Background: complex (MAC) pulmonary disease and lung adenocarcinoma can present with overlapping clinical and radiographic features, creating a significant diagnostic challenge. Radiographic progression during treatment of pulmonary MAC disease is often attributed to inadequate microbiologic response or persistent infection; however, this assumption may delay recognition of a concurrent malignancy, particularly when microbiologic parameters otherwise suggest an adequate treatment response. Case presentation: A 78-year-old woman with bronchiectasis and previous microbiologic isolation of MAC was diagnosed with cavitary pulmonary MAC disease and initiated on guideline-directed multidrug therapy. Despite achieving sputum culture conversion, she developed new chest pain after approximately six months of treatment, and serial imaging demonstrated evolution of a previously cavitary right upper lobe lesion into a predominantly fluid-filled lesion with increasing surrounding consolidation. Bronchoscopy with biopsy revealed invasive pulmonary adenocarcinoma with coexisting necrotizing granulomatous inflammation. She subsequently underwent right upper lobectomy, with final pathology demonstrating a 6.5-cm poorly differentiated adenocarcinoma, negative surgical margins, and no lymph node metastases (pT3N0). Conclusion: This case demonstrates that microbiologic culture conversion in pulmonary MAC disease should not preclude consideration of a concurrent malignant process when radiographic abnormalities continue to evolve. Discordance between microbiologic response and radiographic trajectory should prompt consideration of tissue diagnosis to exclude an underlying malignancy, potentially facilitating earlier diagnosis of lung cancer and preventing delays in definitive treatment.

Source: IDCases

DOI: 10.1016/j.idcr.2026.e02798

Authors: Kavya Kempanna, Ramzia Muhammed Kunhi, Rutvi Shah, Justin M. Oring, Sangeeta Nair-Collins

Institutions: Mayo Clinic, Mayo Clinic in Florida

Language: English

Topic: Mycobacterium research and diagnosis

Subfield: Epidemiology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $1,370