Testicular neuroendocrine tumors (TNETs) are extremely rare. We report a case of a primary TNET and discuss the clinical and histological characteristics, treatment, and prognosis of this tumor. A 47-year-old man had a painless right testicular mass. All tumor markers were negative. The patient underwent a high inguinal radical orchidectomy. Histopathology revealed a well-differentiated neuroendocrine tumor. Radiological investigations showed multiple prominent axillary, supraclavicular, mediastinal, and hilar lymph nodes and no bowel or mesenteric lesions suggesting carcinoid. Once a TNET is diagnosed, it is necessary to rule out the secondary origin in the gastrointestinal tract and lungs. Radical orchiectomy is the treatment of choice for TNETs. Somatostatin analogs can be useful in patients with carcinoid syndrome, induce symptomatic improvement, and control disease progression. As this case highlights, physicians should consider TNETs in the differential diagnosis of testicular masses, as early diagnosis and treatment are crucial for good patient outcomes.