Snapshot A 33-year-old man presents to his physician's office after noticing a mass on his left testicle while showering. He reports this has never happened before and denies any pain or discomfort. On physical examination, there is a firm and fixed mass on the left testicle. Bilateral scrotal ultrasound is performed and significant findings are shown. Introduction Clinical definition testicular malignancy that can be divided into germ cell tumors (~95% of cases and more commonly malignant) which can further divided into seminomas cells can resemble primordial germ cells and early gonocytes nonseminomas cells can be undifferentiated and appear as embryonic stem cells (in embryonal carcinoma) cells can differentiate into yolk sac tumors choriocarcinomas teratomas sex cord-stromal tumors (usually benign) Epidemiology germ cell tumors incidence 6 per 100,000 demographics most common tumor in men 15-34 years of age risk factors cryptorchidism family history infertility Pathogenesis germ cell tumors most originate from intratubular germ cell neoplasia and may progress to a seminoma or nonseminomatous tumor Prognosis ~95% cure is expected with treatment Testicular Tumors Germ Cell Tumor Type Comments Seminoma Most common type of germ cell tumor Peak incidence is in the third decade of life Morphology cells have a large central nucleus with prominent nucleoli clear and watery-appearing cytoplasm ("fried-egg") ↑ placental alkaline phosphatase (PLAP) Similar to dysgerminoma in females Yolk sac tumor Also known as endodermal sinus tumor Most common testicular tumor in infants and children (<3 years of age) Morphology Yellow-white mucinous appearance Schiller-Duval bodies in ~50% of cases α-fetoprotein (AFP) and α1-antitrypsin can be seen on immunocytochemical staining Choriocarcinoma Highly malignant and can metastasize to the lung brain Morphology contains syncytiotrophoblasts (contains hCG) and cytotrophoblasts Laboratory findings ↑ hCG that can result in gynecomastia hyperthyroidism recall that hCG is structurally similar to luteinizing hormone (LH), follicle-stimulating horomone (FSH), and thyroid-stimulating hormone (TSH) Teratoma A testicular tumor with cells that are reminiscent of more than one germ layer Can occur at any age Morphology cells or organoid structures may include neural tissue muscle thyroid-like tissue tissue from the intestinal wall Embryonal carcinoma Mostly affects men at 20-30 years of age Painful More aggressive than seminomas Morphology cells may show glandular patterns papillary convolutions In pure embryonal carcinoma there can be ↑ hCG and normal AFP AFP can be elevated when there is mixed embryonal carcinoma Sex Cord-Stromal Tumors Comments Leydig cell tumor Most cases occur at 20-60 years of age Most commonly presents with testicular swelling gynecomastia may be the first presenting symptom Can produce androgens and estrogens can result in ↓ LH Morphology golden brown and homogenous cut surface cells contain crystalloids of Reinke in their cytoplasm Sertoli cell tumor Most cases are benign These tumors are hormonally silent Non-Hodgkin Lymphomas Comments Testicular lymphoma Most common testicular neoplasm in men > 60 years of age Most common testicular lymphoma is diffuse large B-cell lymphoma These tumors have a higher propensity to involve the central nervous system Presentation Symptoms painless nodule or swelling in one testicle (usually) please refer to above chart for specific clinical presentations Physical exam firm, hard, or fixed mass should raise suspicion it is considered testicular cancer until proven otherwise Imaging Ultrasound indication initial test for the evaluation of a testicular mass modality bilateral scrotum findings seminomas can show hypoechoic lesions without cystic findings nonseminomatous germ cell tumors can show inhomogenous lesions calcifications cystic areas indistinct margins Radiography indication to assess for suspected mediastinal, hilar, or lung metastasis modality chest Computerized tomography (CT) scan indications to detect for metastasis to the retroperitoneal lymph nodes in patients diagnosed with testicular cancer to detect for metastasis to the thorax when the chest radiograph is abnormal or when metastatic disease is highly suspected Studies Labs serum tumor marks AFP hCG lactate dehydrogenase (LDH) Histology refer to chart Differential Orchitis Epididymitis Varicoceles Hydroceles Indirect inguinal hernias Treatment Surgical radical inguinal orchiectomy indication primary treatment for testicular tumors and further treatment is determined by microscopic findings and staging Complications Infertility Metastasis Endocrine abnormalities