Tuberculosis as a differential diagnosis of salivary gland malignancy.

Mycobacterial infection of the salivary glands is extremely rare, even in endemic countries. Differential diagnosis with benign or malignant neoplasms is challenging, and treatment is often delayed. We describe the case of a 62-year-old female patient who presented with a 2-month-old complaint of a right preauricular painless swelling. An ultrasound-guided fine-needle aspiration biopsy was performed, with a resulting lymphocytic infiltrate, without clear atypia. MRI demonstrated a lesion with ill-defined contours, described as probably malignant. Because of this mismatch in results, a core biopsy of the main lesion was performed, demonstrating granulomas with central necrosis, with no mycobacteria detected in PCR or culture. As the lesion continued to enlarge, a new biopsy was ordered, and this time Mycobacterium tuberculosis was detected. Treatment with extrapulmonary tuberculosis therapy was initiated. The sensitivity of PCR and culture combined is only 73% in extrapulmonary tuberculosis. A systematic approach may prevent unnecessary surgical interventions. © BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.