成人男性の陰嚢水腫：原因と治療が必要な時期

最終更新日: 2026年8月28日

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A painless scrotal swelling is one of the commonest reasons men come to an andrology clinic. Most turn out to be a hydrocele — fluid collecting in the space around the testicle. The word most is doing important work in that sentence, which is where this page starts.

• タイ・バンコク病院 泌尿器科センター オンライン予約 02-310-3009 bhquro@bdms.co.th
• サミティベート・シラチャ病院(チョンブリ) 088-022-1445

First: a new swelling is scanned before it is called a hydrocele

The earlier version of this article described hydrocele as benign and never life-threatening, twice. That is true of a hydrocele — and it is the wrong thing to lead with, because the reason every new scrotal swelling gets an ultrasound is that a testicular tumour can present as one.

A tumour can produce a surrounding collection of fluid that hides it completely on examination, and testicular cancer occurs mainly in young men, in whom a painless swelling is easily dismissed. So the sequence is: scan first, reassure second. Once the scan shows fluid and a normal testicle, the reassurance is complete and genuine.

The practical version: a new or enlarging scrotal swelling should be examined and scanned, not watched.

What a hydrocele is

Between the testicle and the scrotal wall lies a thin membrane, the tunica vaginalis, containing a small amount of fluid that lets the testicle move freely. Fluid is continuously produced and continuously reabsorbed. When that balance tips — too much produced, or too little absorbed — fluid accumulates.

A classic hydrocele is soft, painless, and transilluminates: shine a torch against it in a dark room and the whole swelling glows, because light passes through clear fluid. A solid lump does not. It is a crude test and a useful one, and a swelling that does ない transilluminate needs explaining.

You can also usually feel above a hydrocele, whereas a hernia extends up towards the groin and you cannot — one of the ways the two are separated at the bedside.

Why it happens in adults

• 特定できる原因はありません — the commonest situation by some distance, usually developing gradually in a middle-aged or older man through reduced reabsorption.
• Inflammation — infection of the testicle or epididymis, which often leaves a reactive hydrocele behind after it settles.
• Injury、および after surgery — particularly after hernia repair or varicocele repair, where it is a recognised complication.
• Tumour — uncommon as a cause, and the reason for the scan.
• フィラリア症, which remains a cause in parts of Asia and Africa and produces a characteristically thick-walled hydrocele. Worth mentioning to your doctor if you have lived in an endemic area.

Most hydroceles need no treatment

This was absent from the earlier version, which moved from diagnosis straight to surgery — and it is the correct management for a large proportion of men.

A hydrocele that is small, comfortable and not bothering you can simply be left alone. It does not damage the testicle, it does not turn into anything, and it does not have to be removed because it exists. Where one follows an infection, it often resolves by itself over months as the inflammation settles.

Treatment is for size, discomfort, heaviness, interference with sitting, walking or sex, or appearance that genuinely troubles you. Those are legitimate reasons — and so is deciding you would rather not.

If treatment is wanted

• Surgery (hydrocelectomy) — the sac is opened and either removed or turned inside out so fluid can no longer collect. Done under anaesthesia as a day case, and it is the definitive treatment with much the lowest recurrence.
• Needle drainage — quick and done in the clinic. The earlier version described it as carrying a higher recurrence rate, which understates it: drainage alone nearly always refills, often within weeks to a few months, because nothing has been done about the sac that produces the fluid. Injecting a sclerosant afterwards improves durability considerably and is what makes the approach worth considering at all — usually for a man who is unfit for or unwilling to have an operation.

One firm rule: a hydrocele is not drained until a tumour has been excluded on ultrasound. Putting a needle into an undiagnosed scrotal mass is exactly what should not happen.

What the operation can cost you

Also absent from the earlier version, and it belongs on a page a man reads before consenting to a procedure he does not medically need.

• Bleeding into the scrotum — the commonest problem, and the reason for a compression dressing and support afterwards.
• 感染症、および swelling that takes weeks to settle — the scrotum looks worse before it looks better, which surprises men who were expecting an immediate result.
• Persistent scrotal ache in a minority.
• 再発, which is uncommon after surgery but not impossible.

Symptoms that need attention rather than an appointment

タイで緊急の場合は、次の番号に電話してください 1669.

• 突然の激しい睾丸痛 — that is not a hydrocele and is treated as ねじり until proved otherwise, with what can be saved decided in hours.
• 睾丸そのものの固い塊, or a swelling that does not transilluminate — needs assessing promptly rather than assuming it is fluid.
• Rapid enlargement, or swelling accompanied by weight loss, breast tenderness or a lump in the abdomen.
• Fever with a red, hot, painful scrotum.
• A swelling you cannot get above, that changes size with standing or straining — more suggestive of a hernia, which has its own risks.

陰嚢水腫に関するよくある質問

Is a hydrocele dangerous?

A confirmed hydrocele is benign — it does not damage the testicle and does not become cancerous. The important qualification is 確認済み: a testicular tumour can present as a scrotal swelling with surrounding fluid, so a new swelling is scanned before it is called a hydrocele. After a normal scan the reassurance is complete.

Does it have to be treated?

No. A hydrocele that is small and comfortable can be left alone indefinitely, and one following an infection often resolves by itself over months. Treatment is for size, discomfort, heaviness, interference with daily life or appearance — not because it exists.

Can it just be drained with a needle?

It can, and drainage alone nearly always refills within weeks to months because the sac producing the fluid is untouched. Adding a sclerosant improves durability and makes it a reasonable option for someone unfit for or unwilling to have surgery. Nothing is drained until a tumour has been excluded on ultrasound.

How do I tell a hydrocele from something serious at home?

You cannot, reliably, and should not try to. A hydrocele is typically soft, painless and transilluminates when a torch is held against it in a dark room, and you can usually feel above it. A firm lump, a swelling that does not transilluminate, sudden pain or rapid enlargement all need examining.

Will surgery affect fertility or testosterone?

Hydrocelectomy does not remove the testicle and is not expected to affect hormone production. The recognised problems are bleeding into the scrotum, infection, prolonged swelling and persistent ache in a minority, with recurrence uncommon.

診察のご予約について

Dr. Soarawee Weerasopone の診察場所は次のとおりです Bangkok Hospital Headquarters また、チョンブリー県の Samitivej Sriracha Hospital でも次の曜日に診察を行っています 088-022-1445. Bring any previous scrotal ultrasound, and note roughly when the swelling appeared and whether it has been changing.

来院が難しい海外の患者さんを含め、バンコク病院の遠隔診療をご利用いただけます。事前に泌尿器科へ次のメールアドレスまでご連絡のうえ、ご予約ください: bhquro@bdms.co.th。サミティベート・シラチャー病院は対面診療のみです。費用に関するお問い合わせには病院が対応しており、本ウェブサイトでは対応しておりません。 A scrotal swelling needs examining in person; it cannot be assessed remotely.

免責事項: 本コンテンツは、Bangkok Hospital Headquarters に勤務する泌尿器科専門医(認定医)の Dr. Soarawee Weerasopone が執筆・監修したもので、教育目的のみを意図しています。個々の方に対する医学的助言、診断、処方ではなく、個人メッセージやソーシャルメディアを通じて助言、診断、処方を行うことはありません。Dr. Soarawee は公開のソーシャルメディアアカウントを運営しておらず、彼の名前で個別相談を提供するアカウントは詐欺です。タイで緊急の場合は、次の番号に電話してください 1669.