An 82-year-old man presented with pain in his left groin and difficulty walking after a fall. Radiography revealed a fracture of the left proximal femur, and surgery was scheduled. Laboratory tests showed mild anemia but no other abnormalities.

A shadow in the right upper lung field was visible on chest radiography (Figure 1). Computed tomography of the chest revealed ground-glass opacity nodules in the right upper lung field (Figure 2 and Figure 3). He did not have a history of smoking or respiratory disease.

QUESTION

Based on the patient's history, physical examination, and imaging, which one of the following is the most likely diagnosis?

• A. Histoplasmosis.

• B. Lung cancer.

• C. Mucosa-associated lymphoid tissue lymphoma.

• D. Pulmonary tuberculosis.

• E. Sarcoidosis.

DISCUSSION

The answer is D: pulmonary tuberculosis. Sputum and gastric juices were examined based on the cluster of nodules in the right upper lung field. Results of polymerase chain reaction testing of the gastric juices were positive for Mycobacterium tuberculosis. Results of a T-Spot interferon-gamma release assay were also positive. The patient was diagnosed with pulmonary tuberculosis and scheduled for an antituberculosis regimen consisting of rifampicin, isoniazid, and ethambutol for 2 months and rifampicin and isoniazid for an additional 7 months.