Endobronchial Enigma: A Clinically Rare Presentation of Nocardia beijingensis in an Immunocompetent Patient

Abstract

Nocardiosis is an opportunistic infection caused by the Gram-positive weakly acid-fast, filamentous aerobic Actinomycetes. The lungs are the primary site of infection mainly affecting immunocompromised patients. In rare circumstances even immunocompetent hosts may also develop infection. Diagnosis of pulmonary nocardiosis is usually delayed due to nonspecific clinical and radiological presentations which mimic fungal, tuberculous, or neoplastic processes. The present report describes a rare bronchoscopic presentation of an endobronchial nocardial mass in a 55-year-old immunocompetent woman without underlying lung disease. The patient exhibited signs and symptoms of unresolving community-acquired pneumonia with a computed tomography (CT) scan that showed a space-occupying lesion and enlarged paratracheal lymph node. This patient represents the unusual presentation of pulmonary Nocardia beijingensis as an endobronchial mass. Pathology obtained during bronchoscopy demonstrated polymerase chain reaction (PCR) confirmation of nocardiosis. Symptoms and clinical findings improved with antibiotic treatment. This patient emphasizes the challenge in making the diagnosis of pulmonary nocardiosis, especially in a low risk host. A literature review presents the difficulties and pitfalls in the clinical assessment of such an individual.

Figure 1

CT scan of the lung, axial view: the horizontal arrow is pointing toward nocardial mass in the right lower lob, while the longitudinal arrow is pointing toward nocardial cavitary lesion in the same lobe.

Figure 2

Bronchoscopic images: the arrows are pointing to different views of nocardial white friable lesions (a) and mass (b) in the right lower lobe.

Figure 3

(a) Gram stain (×40). Arrows point toward Gram-positive filamentous microorganism. (b) Ziehl-Neelsen stain (×100). Arrows point toward partially acid-fast beaded branching filaments.