• Clinical science

Testicular tumors

Summary

Testicular tumors most commonly occur in men between 20 and 35 years of age, and are the most common solid malignancy in this group. Most often, patients present with a painless nodule or swelling of the testis. Diagnosis is made primarily based on palpation and findings on testicular ultrasound. Diagnostic staging further includes an abdominopelvic and chest CT, determination of serologic tumor markers (AFP, HCG, LDH), and radical inguinal orchiectomy of the affected side to confirm the diagnosis and to evaluate the histopathology (seminoma vs. nonseminoma). The necessity and choice of adjuvant treatment depends on tumor pathology, staging, and prognosis. Treatment options include active surveillance, retroperitoneal radiotherapy, retroperitoneal lymph node dissection, and platinum-based chemotherapy. The overall prognosis of testicular tumors is excellent; patients can often be cured even in advanced, metastatic stages.

Epidemiology

  • Most common solid malignant tumor in young men in the US
  • Peak incidence: 20–35 years; (nonseminomas peak in the third decade, seminomas in the fourth decade of life)

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

References:[2][3][4]

Classification

Testicular tumors are classified according to pathology.

Overview of testicular tumors
Type of tumor Frequency AFP HCG Characteristics Pathology
Germ cell tumors of the testis (95%)
Seminoma
  • ∼ 40%
  • –/↑
  • Malignant tumor that has slow growth and late metastases
  • Good radiosensitivity
  • Better overall prognosis compared to nonseminomas
  • Most common testicular tumor
  • Increased placental ALP
  • Comparable to ovarian dysgerminoma in women
  • Macroscopic findings: uniform white cut section
  • Microscopy
    • Fried egg cell appearance
    • Cells have an abundance of watery cytoplasm
    • Fibrous septae divide the tumor into lobules
Nonseminoma tumors Embryonal carcinoma
  • ∼ 25%
  • –/↑
  • Macroscopic findings: grey-white regressive changes with hemorrhage, necrosis, and cysts
  • Microscopy: glandular or papillary pattern
Teratoma
  • ∼ 25%
  • Rare in adults, but common in children
  • Typically benign but may be malignant in adults (teratocarcinoma)
  • Composed of tissue from different germinal layers.
  • May be immature or may contain fully differentiated elements of muscle, cartilage, bone, teeth in mature teratomas
Testicular choriocarcinoma
  • ∼ 5%
  • ↑↑
Yolk sac tumor
  • ∼ 5%
  • ↑↑
  • Most common prepubertal testicular tumor [5]
  • Aggressive tumor with high malignant potential
Mixed germ cell tumors
  • ∼ 30% [6]
  • –/↑
  • –/↑
  • Heterogeneous cut surface with solid areas, hemorrhage, and necrosis
Non-germ cell tumors of the testis (5%)
Leydig cell tumors
  • ∼ 2%
  • Rare tumors which arise from the hormone-producing stromal cells of the testes
  • Usually develop after the age of 4
  • Produce large amounts of testosterone and a small amount of estrogen, progesterone, and corticosteroids
  • Malignant transformation is very rare.
Sertoli cell tumors
  • < 1%
Secondary testicular tumors Lymphoma
  • Most common testicular tumor in men > 60 years of age
  • Usually diffuse large B-cell lymphomas [7]

HCG is always elevated in choriocarcinoma and sometimes elevated in seminoma. AFP is always elevated in yolk sac tumors. Both AFP and HCG may be elevated in mixed germ cell tumors.

Testicular tumors metastasize early into the retroperitoneum via the lymphatic system (drain to the para-aortic lymph nodes first), with the exception of early hematogenous metastasizing choriocarcinomas.

References:[8][9][10][10][11]

Clinical features

Until proven otherwise, a firm nodule on the testis should be considered cancer!

References:[1][12]

Subtypes and variants

Extragonadal germ cell tumors

References:[14][15][16]

Stages

Staging of testicular tumors is based on the American Joint Committee on Cancer (AJCC) groups, which combines TNM stage and serum tumor marker levels.

Simplified AJCC classification
Stage Description
Stage I
Stage II
Stage III

Diagnostics

Suspicion of a testicular tumor is usually established based on the clinical findings and ultrasound (to localize the tumor).

If a testicular tumor is suspected, the testis should be removed and sent to pathology. Transscrotal biopsy should not be conducted because of the risk of tumor seeding!

References:[1][17]

Differential diagnoses

Differential diagnosis of painless testicular swelling
Condition Clinical features Ultrasound
Testicular tumor
  • Usually painless mass (however, may feel dull ache or "heavy" sensation in the testicle)
  • Palpation of solid mass
  • Negative transillumination test
  • Solid mass with variable echogenicity
Hydrocele testis
  • Fluctuant swelling of the scrotum
  • Palpation of an elastic soft swelling
  • Positive transillumination test
  • Hypoechoic mass around the testis
Varicocele testis
  • Usually painless ; swelling may be reduced when supine
  • Visible or palpable strands and “bag of worms” sensation
  • Negative transillumination test
  • Dilated hypoechoic pampiniform vessels
Spermatocele testis
  • Fluctuant swelling of the upper testicular pole
  • Positive transillumination test
  • Hypoechoic dilation of epididymal duct or rete testis
Scrotal hernia
  • Visible groin protrusion
  • Bowel sounds on auscultation over scrotum
  • Herniated bowels

References:[18]

The differential diagnoses listed here are not exhaustive.

Treatment

Surgery

Adjuvant radiotherapy and chemotherapy

Adjuvant treatment for testicular cancer
Staging according to the classification Seminoma Nonseminoma
Stage I

Stage II

Stage III
  • Chemotherapy (depending on prognosis): BEP1 or EP2 followed by evaluation of any residual disease that may require resection
1BEP = chemotherapy with bleomycin, etoposide, and cisplatin, 2EP = chemotherapy with etoposide, cisplatin, 3RPLND= retroperitoneal lymph node dissection

References:[19][20][21][9]

Prognosis

  • The overall prognosis of testicular tumors is excellent, with a high cure rate and 5-year survival rates of > 95%.
  • Even in advanced, metastatic stages, testicular tumors are often curable.

Testicular tumors, particularly seminomas, are one of the few cancers that can be cured even in very advanced stages with adequate treatment. Patients with nonseminomas have a significantly poorer prognosis but still an excellent overall survival rate!
References:[22]