Metastases to testis

Metastases to testis are a very rare cause of a testicular mass and may be bilateral in up to 15% of patients. 

Epidemiology

Metastases to the testes are apparent in ~0.04% of autopsy studies in patients with known malignancy. The average age is 57 years, much older than the primary age for primary testicular cancer ². 

Pathology

The literature suggests that the rarity of metastases to the testes may be due to:

• lower temperature of the scrotum, so the malignant cells find it more difficult to proliferate ⁹
• testes are a 'sanctuary' site - due to the blood-testicular barrier ¹⁰

Etiology

In adults a malignant testicular lesion is much more likely to be a primary. Even so-called common sources are rare. The largest series of 20 cases of metastases to the testes, over a ten-year period, found the majority to be from leukemia ¹⁰.

Common ⁹

• leukaemia (most common) ⁸
• lymphoma
• prostate (most common solid tumor origin)
• lung
• colorectal cancer
• renal cell carcinoma
• malignant melanoma

Very rare

• thyroid cancer
• esophageal adenocarcinoma ⁴
• pancreatic adenocarcinoma ⁵
• gastric carcinoma ⁶
• upper tract urothelial carcinoma ⁷
• hepatocellular carcinoma ⁹
• bladder cancer ⁸

In children, sources include:

• neuroblastoma
• Wilms tumor
• rhabdomyosarcoma

See also

• testicular cancer
• unilateral testicular lesions
• bilateral testicular lesions
• paratesticular lesions