Pulmonary malakoplakia coexistent with tuberculosis of the hilar lymph node mimicking malignancy.

Pulmonary malakoplakia is a disease that is difficult to diagnose because its symptoms vary from those mimicking bronchogenic carcinoma to pneumonitis-like tuberculous infections. Malakoplakia is an unusual inflammatory condition characterized by the accumulation of macrophages with diagnostic Michaelis-Gutmann bodies. In this study, an immunocompromised patient with a tumor mass in the upper lobe of the right lung coexisting with hilar node enlargement is presented. A thoracoscopic biopsy revealed pulmonary malakoplakia with tuberculosis of the hilar lymph node. Microbiologic cultures were positive for acid-fast positive bacilli from the hilar node specimen, and negative for any other microorganisms such as Rhodococcus equi, but positive for Escherichia coli from the lung specimen. The significance of these findings and the coincidental association between malakoplakia and tuberculosis are discussed.