Lump in the testicle: causes, red flags and when to get it checked

The testicle contains sperm-producing tissue and sits in a sac with the epididymis, a coiled tube that stores sperm. Lumps can arise from the testicle itself, from the epididymis, from fluid around the testicle or from veins. Finding where the lump sits and its character is the first step, but ultrasound confirms it.

• Epididymal cyst (spermatocele): a smooth, painless, pea-sized lump above or behind the testicle, separate from it.

• Hydrocele: painless swelling from fluid around the testicle, which can be translucent.

• Varicocele: a soft, "bag of worms" swelling of veins, more often on the left, which can ache.

• Epididymo-orchitis: a tender swollen testicle or epididymis with fever, often from infection.

• Inguinal hernia extending into the scrotum.

• Testicular torsion: sudden severe pain and swelling, which is an emergency.

• Testicular cancer: usually a painless firm lump or enlargement in the testicle, or a dragging or heavy feeling.

• Other tumours, a haematoma after injury, and rare inflammatory causes.

A firm, hard or irregular lump in the testicle itself, painless or mild ache, an enlarging testicle, a feeling of heaviness, a history of undescended testicle, previous testicular cancer, family history, back pain, a breast lump or tenderness, or breathlessness may indicate testicular cancer.

• Call 999 or go to A&E now: sudden severe testicular pain, swelling, nausea or vomiting (possible torsion; surgery is time-critical).

• Same-day GP or urgent care: a tender hot swollen testicle with fever.

• See a GP within days (urgent suspected cancer pathway): any new lump or swelling in the testicle, even if painless.

• Routine GP: a known soft, stable swelling that you want reviewed.

The doctor asks when the lump appeared, whether it is painful, changes in size, injury, infection, undescended testicle, fertility, family history and other symptoms. They examine both testicles and the scrotum, check whether the lump is separate from the testicle, whether it transilluminates, and examine the abdomen and neck.

• Scrotal ultrasound: the key test to distinguish cystic from solid lumps.

• Blood tumour markers (AFP, hCG, LDH): if a solid lump is found.

• Urine test and swabs: for infection.

• CT scan of chest, abdomen and pelvis: staging if cancer is confirmed.

• Sperm banking is discussed before treatment where relevant.

Examine your testicles monthly after a warm bath or shower, rolling each gently between thumb and fingers, noting any change; a smooth cord-like epididymis behind the testicle is normal. Do not wait and watch a new lump. If cancer is found, treatment is highly effective and fertility preservation is discussed.

The NHS route is a GP, then urgent ultrasound and urology under the suspected cancer pathway. Private urology offers same-week ultrasound and consultation, with urgent cases going to the NHS emergency route.