Cutaneous nocardiosis with discharging sinus clinically mimicking tuberculosis diagnosed by cytology

Nocardiosis is primarily a pulmonary infection commonly seen in immunocompromised individuals. However, lymphocutaneous nocardiosis is observed in immunocompetent individuals often after trauma. The clinical and cytomorphological features of lymphocutaneous nocardiosis closely mimic the most common infections in India such as tuberculosis and mycetoma (very common cutaneous infection with discharging sinus). As it is crucial to differentiate nocardiosis from tuberculosis, to avoid unnecessary antitubercular treatment, special stains like modified Ziehl-Neelsen stain and Gram stain can be employed to differentiate the morphology of Nocardia from tuberculosis. Fine-needle cytology from these cutaneous lesions helps in yielding adequate material for rapid and accurate diagnosis of immediate specific antibiotic treatment. We report a rare case that presented with clinical diagnosis of tuberculosis but turned out to be nocardiosis on cytomorphology with simple and most feasible fine-needle aspiration method of tissue diagnosis and scrape cytology.