A malignant tumor of the testis (one or both), most often of germ cell origin (95%), which may be diagnosed as primary or metastatic cancer. Common presentation includes painless swelling, palpable mass or enlargement in the testis, orchidalgia, fatigue, and infertility. Other symptoms may be flank pain and dull or heavy abdominal sensation. Patients with metastatic disease, depending on the location of the metastasis, may present with gastrointestinal (GI) symptoms (nausea, vomiting, GI hemorrhage, anorexia), edema of extremities, bone pain, back pain, central nervous system abnormalities, cough, dyspnea, or neck mass. Patients with cryptorchidism have greater risk for testicular cancer.

Nonseminomatous tumors most commonly occur in patients aged 15-35, while seminomatous tumors target men a decade older. Germ cell malignancies of the testis are typically associated with a specific cytogenic irregularity (il2p). Non-germ cell tumors may arise in Leydig or Sertoli cells, or lymphomas, with non-Hodgkin lymphoma more common in men over age 60.

Treatment depends on clinical staging and includes surveillance, chemotherapy, lymph node removal (nerve-sparing retroperitoneal lymph node dissection, or RPLND), adjuvant chemotherapy, orchiectomy, and radiation therapy.