Primary testicular neuroendocrine tumors (TNETs) are sporadic, accounting for only 0.23% of all testicular tumors. Few cases have been reported in the literature, and no uniform treatment protocol exists. We report a case of a primary TNET with liver lymph node metastasis diagnosed at the age of 24 years and discuss its clinicopathological features, diagnosis, differential diagnosis, treatment, and prognosis.

We report the case of a 24-year-old patient with a primary TNET with liver lymph node metastasis. The patient was found to have a right testicular swelling of about 3 cm × 4 cm in size with unclear borders and no testicular pressure pain seven years ago without any examination or treatment. One month ago, an ultrasound examination was performed for persistent enlargement of the right testis, which showed an occupying lesion of the right testis approximately 110 mm × 102 mm × 82 mm in size. Magnetic resonance imaging scan of the testis (plain scan) showed that the right testis was an occupying lesion with inhomogeneous density and mixed signal, the boundary was still clear, and the possibility of seminoma was considered; chest X-ray and computed tomography did not show any apparent abnormalities. The patient underwent radical orchiectomy, and the pathological examination suggested a right TNET with a typical carcinoid tumor histological type. One month after the surgery, the patient received nine cycles of lanreotide chemotherapy at a dose of 90 mg/mo without adverse effects. No distant lymph node or other organ metastases were detected at follow-up. He is in good physical condition and attends regular follow-up visits.

Neuroendocrine tumors are rare in clinical practice, and the diagnosis mainly relies on the characteristics of microscopic tumor cells and immunohistochemical features. Treatment involves radical orchiectomy. If it is accompanied by distant lymph node metastasis and the metastatic lesion can be resected, it should be surgically removed; if it cannot be resected, growth inhibitor analog octreotide or lanreotide chemotherapy can be administered to obtain good results, with close postoperative follow-up to prevent recurrence and metastasis.

• Testis
• Neuroendocrine tumor
• Immunohistochemistry
• Differential diagnosis
• Somatostatin analog
• Lanreotide
• Liver metastasis
• Treatment
• Case report