Granulomatous orchitis is a rare disease with mixed chronic and granulomatous inflammation. Various factors cause granulomatous inflammation in the testicles, and it may accompany malignancies. Radiologically, granulomatous orchitis can be confused with malignancy. This paper presents the differential diagnoses of granulomatous orchitis. A 52-year-old man with testicular swelling was referred to the urology clinic. A palpable mass was detected by physical examination. Ultrasonography revealed a solid, heterogeneous 2.5 cm mass suspected as a malignancy in the right testes. The patient underwent elective orchiectomy. Microscopically, the testicle showed necrotising granulomatous inflammation accompanied by an inflammatory infiltrate that destroyed the testicular structure and caused rete testis hyperplasia. Radiologically, granulomatous orchitis can be confused with malignancy. Sufficient samples should be taken to exclude malignancy. Idiopathic granulomatous orchitis can be diagnosed after excluding all possible causes of granulomatous orchitis.