Organizing Pneumonia with NGS False-Positive Imaging Resembling Tuberculosis: a Case Report

Area of Science:

• Pulmonary pathology and diagnostics
• Infectious disease mimicry in the lung

Background:

• Organizing pneumonia (OP) is a pathological pattern characterized by granulation tissue in small airways and alveoli.
• OP imaging can be variable, often necessitating histopathology for definitive diagnosis, especially with atypical presentations.
• This case involved OP mimicking pulmonary tuberculosis with misleading next-generation sequencing (NGS) results.

Observation:

• Chest CT revealed a nodular high-density shadow in the right lower lung lobe.
• Bronchoalveolar lavage fluid underwent NGS, showing high sequence counts for Moraxella osseae and Prevotella melanogaster.
• Initial misdiagnosis was pulmonary tuberculosis based on imaging and NGS findings.

Findings:

• Lung histopathology confirmed organizing pneumonia, revealing fibrous emboli and necrotic material within the alveolar lumen.
• The NGS results for Moraxella osseae and Prevotella melanogaster were ultimately deemed non-diagnostic for active infection in this context.
• The patient's condition was clarified as organizing pneumonia, distinct from tuberculosis.

Implications:

• Physicians should exercise caution with NGS results, particularly when they conflict with clinical and imaging findings.
• In cases of diagnostic uncertainty or ineffective anti-infective treatment, prompt lung tissue biopsy for histopathological examination is vital.
• Accurate pathological diagnosis is essential to differentiate organizing pneumonia from other conditions like pulmonary tuberculosis and avoid inappropriate treatment.