Hydrocele

Overview

A hydrocele is an accumulation of fluid within the tunica vaginalis — the sac that surrounds the testicle. It presents as a smooth, non-tender swelling of the scrotum that transilluminates (light shines through it). Hydroceles are relatively common in adult men and are the most frequent cause of painless scrotal swelling.

Primary (idiopathic) hydrocele is by far the most common type in adults. There is no identifiable underlying cause; fluid simply accumulates between the layers of the tunica vaginalis because secretion exceeds reabsorption. Primary hydroceles are benign and cause no harm to the testicle itself.

Secondary hydrocele develops as a reaction to an underlying condition affecting the testicle or epididymis. Causes include:

• Epididymo-orchitis (infection or inflammation)
• Testicular torsion
• Trauma to the scrotum
• Testicular tumour (an important cause not to miss)
• Inguinal hernia surgery

For this reason, any new hydrocele should be assessed with a scrotal ultrasound, even when there are no other symptoms, to exclude a secondary cause.

Symptoms

The characteristic presentation is a smooth, painless swelling of one side of the scrotum (less commonly both sides). The swelling:

• Develops gradually and is usually not painful
• May cause a sensation of heaviness or dragging discomfort if large
• Transilluminates — a torch held against the swelling shows the scrotum lit up, confirming the fluid-filled nature

Acute pain associated with a scrotal swelling should prompt urgent assessment to exclude testicular torsion (twisting of the testicle), which is a surgical emergency.

Diagnosis

• Scrotal ultrasound — the key investigation; confirms the hydrocele, measures its size, and critically assesses the testicle within the fluid to exclude any testicular mass, abnormality, or tumour; Doppler assessment also evaluates blood flow to the testicle
• Clinical examination — a hydrocele transilluminates, is typically non-tender, and the testicle cannot be palpated separately from the swelling

Blood tumour markers (AFP, bHCG) are measured if the ultrasound raises any concern about a testicular tumour.

Treatment

Observation Small, asymptomatic hydroceles that have been confirmed to be primary on ultrasound do not require treatment. Periodic observation is appropriate, with re-assessment if the size increases significantly or if symptoms develop.

Surgical repair (hydrocelectomy) Surgery is recommended when:

• The hydrocele causes significant discomfort or cosmetic concern
• It is large and uncomfortable
• There is uncertainty about whether it is primary

The procedure is performed as a day case under general or spinal anaesthesia. A small incision is made in the scrotum, the hydrocele sac is drained, and the sac is surgically obliterated or excised to prevent recurrence. The testicle is inspected and returned to the scrotum. Recovery takes one to two weeks.

Aspiration Needle aspiration of the fluid provides temporary relief but has a high recurrence rate. It may be used in men who are not fit for surgery or who prefer to avoid an operation. Combining aspiration with injection of a sclerosant agent (sclerotherapy) can delay recurrence but is less reliably effective than surgical repair.