Testicular Swelling as an Initial Presentation of a Patient With Metastatic Gastric Cancer

Gastric cancer is one of the most common cancers and the second most common cause of cancer-related death worldwide. ¹ Patients with an early-stage gastric cancer are often asymptomatic, and about 30% to 40% of patients present with distant metastases. ² The most common sites of metastasis are the liver, peritoneum, and the lymph nodes. In more advanced stages, gastric cancers spread to the lungs, brain, bones, soft tissues, and other sites. Krukenberg tumors are classic but rare occurrences of gastric cancer metastasis to ovaries in females. In men, it is rare for gastric cancer to metastasize to the testes. Only a few cases of testicular metastasis from gastric cancer have been reported in the literature. ^3-5

Primary testicular neoplasms typically present with unilateral testicular swelling. In rare instances, testicular swelling can be an initial presentation of a metastatic cancer. In this article, we report a man who initially presented with right testicular swelling and was eventually diagnosed with a secondary testicular cancer from an aggressive metastatic gastric adenocarcinoma.

Case Presentation

A 43-year-old male presented to his primary care physician with a 6-month history of right testicular swelling and unintentional weight loss of 33 pounds. An ultrasound of the scrotum and the testes showed a 4.5-cm hypoechoic and predominantly cystic mass in the right testis. Serum levels of β-human chorionic gonadotropin, α-feto protein and lactate dehydrogenase were within normal limits.

A primary testicular neoplasm was suspected. The patient underwent a right-sided inguinal orchiectomy. The pathology of the resected testis revealed an intestinal type adenocarcinoma with mucinous and signet-ring cell features (Figure).

A staging Fluorine-18 fluorodeoxyglucose positron emission tomography scan revealed extensive hypermetabolic peritoneal nodules consistent with peritoneal carcinomatosis. The patient started palliative chemotherapy with 5-fluorouracil and oxaliplatin but rapidly declined with progressive abdominal symptoms after completion of 2 cycles. He discontinued chemotherapy and eventually opted for supportive care focusing on comfort.

Discussion

Testicular neoplasm is the most common solid tumor in men aged 20 to 34 years in the US.6 More than 90% of testicular neoplasms are germ-cell tumors and originate from the testes. ⁶ Secondary neoplasms of the testes from solid tumors are rare. In an autopsy series, secondary neoplasms from solid tumors represented 4.6% of all testicular neoplasms. ⁷ The reported frequencies of primary sites of origin vary based on the report. In a relatively large series, the most common solid tumors of origin were the prostate (35%) and lungs (20%). ⁸ Among hematologic malignancies, lymphomas may originate from or secondarily involve the testes. Primary testicular lymphomas account for approximately 5% of testicular neoplasms and commonly occur in men aged > 60 years. ⁹ Testicular involvement of acute myeloid or lymphoid leukemia may happen at diagnosis, but relapses of acute leukemia in a testicular site are more common and well recognized. ^10,11