A 42-year-old man presented to the urology clinic with a 2-month history of painless enlargement of the left testicle. He reported no fevers, night sweats, weight loss, respiratory symptoms, or urethral discharge. The physical examination was notable for an enlarged, firm, nontender left testicle. Magnetic resonance imaging of the pelvis showed a lobulated left testicular mass with heterogeneous enhancement (Panel A). Testing for serum tumor markers for testicular cancer was negative. Owing to concern about testicular cancer, a radical inguinal orchiectomy was performed. Gross examination of the excised testis showed necrotic nodules (Panel B), and histopathological examination showed granulomatous inflammation with caseous necrosis (Panel C) and acid-fast bacilli (Panel D, arrows). A real-time–polymerase-chain-reaction assay identified Mycobacterium tuberculosis. Computed tomography of the chest was normal. A diagnosis of testicular tuberculosis was made. A 9-month course of antituberculosis therapy was prescribed. At follow-up 1 year after the initial presentation, the patient was in good health.