Scrotal swelling: should I be worried?

Written by: Mr Simon Brewster
Edited by: Lisa Heffernan

The normal scrotum is a pouch consisting of a thin muscle layer (dartos) and skin which hangs down between a man's two legs, his penis in front and his perineum behind (space between scrotum and anus). The scrotum should contain a testicle on each side and its epididymis tubing hanging by their "spermatic cord", which contains blood vessels and the vas deferens. Swelling can develop in relation to any of these structures during childhood or adulthood. The swelling may be made of liquid or solid tissue; the vast majority are benign, grow slowly and are not serious.


Mr Simon Brewster talks about the symptoms of scrotal swelling, the causes and how a urologist diagnoses and treats this in men.

Is scrotal swelling always painful?

Scrotal swellings are often painless or mildly uncomfortable rather than painful, unless they appear suddenly due to trauma, acute infection, or a twisting of the testicle (" torsion ") that cuts off its blood supply. These exceptions will tend to be very painful and will necessitate emergency assessment. Occasionally, scrotal swellings made of fluid can grow large enough to interfere with fitted clothing and the ability to pass urine in a straight direction, which becomes a nuisance!

What causes scrotal swelling?

The most common scrotal swellings are due to liquid cysts of the epididymis and hydrocoeles of the sack containing the testicle. These are almost always benign and often require no treatment.

Other causes include:

  • A previous vasectomy may cause a degree of long-term uncomfortable swelling of the epididymis.
  • A large hernia arising in the groin can pass downwards into the scrotum, occasionally becoming very bulky.
  • Varicose veins of the spermatic cord ( varicocele ) can look and feel like a "bag of worms"; they can cause discomfort and lower sperm count, although most men are not aware of them.
  • Testicular cancer is the most serious cause of scrotal swelling, this looks like a hard lump arising from the testicle which is usually painless. Thankfully these are quite rare. The most common age for testicular cancer to develop is between the age of 25 and 45 years.


How does a urologist identify the cause of scrotal swelling?

A urologist will carefully examine the swelling to assess its composition and relationship to the structures within the scrotum. A light may be shone through the swelling which can confirm if the swelling is composed of clear fluid. A sample of urine is usually tested to rule out any associated infection. After this clinical assessment, an ultrasound scan is usually requested to gain further information about the swelling.


What are my treatment options?

If testicular cancer is suspected, removal of the testicle and its covering layers is urgently performed. If very severe, sudden onset pain is associated with swelling, testicular torsion may be suspected and an emergency scrotal exploration to untwist and fix the testicle with stitches (and the other testicle too) is urgently required to save the testicle from being lost due to a lack of blood supply.


If an infection is the cause, pain relief and antibiotics are the mainstays of treatment. A varicocele can be treated, if necessary, using an interventional radiology procedure called embolization. If a groin hernia is suspected to be the cause of scrotal swelling, treatment involves repairing the hernia (which should be carried out by a general surgeon rather than a urologist).


In many cases of small harmless fluid-filled scrotal swellings, no treatment is necessary. However, if there is significant discomfort or bulkiness, the fluid can be drawn out using a needle and syringe under local anaesthetic, although the fluid commonly re-accumulates. A definitive day-case operation to remove a cyst or hydrocele under a full anaesthetic is a much better long-term treatment.


Do you have more questions regarding scrotal swelling? Contact Mr Simon Brewster for a full consultation.

By Mr Simon Brewster

Mr Simon Brewster is a consultant urological surgeon with more than 33 years' experience of clinical practice in urology. With a private practice in Oxford running alongside his senior NHS consultant position, Mr Brewster offers state-of-the-art care for the diagnosis and management of prostate cancer, benign prostate enlargement symptoms, prostatitis, urinary tract infections (UTI), scrotal conditions and blood in the urine (haematuria).

After qualifying as a doctor from London's Charing Cross Hospital in 1986 with a first class degree in anatomy and honours in pathology, Mr Brewster undertook his training in surgery and a doctorate research thesis based in Bristol. In 1998 he was appointed as a consultant in Oxford and pioneered the prostate cancer and HoLEP services there. He has led the University Hospitals department with teaching, clinical management, clinical governance and as an elected staff governor for the NHS Foundation Trust. He is a Fellow and Tutor at Hertford College, Oxford. Nationally and internationally, Mr Brewster has influenced specialist training and auditing of surgical outcomes by organising two major conferences and has sat on committees of the British Association of Urological Surgeons (BAUS) and the Uro-oncology Board of the European Association of Urologists (EAU).

Mr Brewster performs MRI-targeted prostate biopsy, diagnostic bladder examinations (cystoscopy) and a wide range of surgery with a high level of patient satisfaction. For prostate and bladder symptoms he offers all medical options and recent surgical innovations including holmium laser enucleation (HoLEP), BIPOLAR TURP and Rezum steam ablation which have the advantages of reduced bleeding, side-effects and a very short hospital stay compared to traditional prostate surgery. He also has considerable experience with ultrasound-guided prostate brachytherapy, gel spacer implants prior to prostate radiotherapy and day-case injections to treat incontinence after prostatectomy. Mr Brewster is hoping to offer patients the new  Water-jet prostate AquaAblation treatment in the near future. 

Mr Brewster maintains an active interest in research and education; he has produced over 90 publications in books and peer-reviewed journals. He is a co-author of the very popular Oxford Handbook of Urology, now in its 4th edition. He undergoes annual appraisal and revalidates with the GMC every five years. With extensive experience in patient care and urological surgery when necessary, Mr Brewster offers a comprehensive evidence-based and personalised service to private patients within and beyond Oxfordshire.

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