Smooth, extratesticular, spherical cysts in the head of the epididymis are not uncommon in adult men. They are benign and do not usually require treatment. It is important to appreciate when they might be significant and when further investigation or treatment is recommended.
Epididymal cysts usually develop in adults around the age of 40. Epididymal cysts are rare in children and when they occur, usually present around puberty.Cysts are found in 20-40% of asymptomatic patients having scrotal ultrasound for other reasons but most of these are spermatoceles.The prevalence in the general population is difficult to estimate.
Patients usually present having noticed a lump. This often causes a great deal of anxiety and clinical examination can enable reassurance.
- Often epididymal cysts are multiple and may be bilateral.
- Small cysts may remain undetected and asymptomatic. Small cysts are tolerated by patients. However, once epididymal cysts get large (with size equivalent to the size of a testicle) they are, unsurprisingly, more likely to present for removal.
- As they are cystic and fluid-filled they are well defined, fluctuant and will transilluminate.
- As they arise in the epididymis, the testis is palpable quite separately from the cyst (unlike a hydrocele where the testis is palpable within the fluid filled swelling).
- Extratesticular, fluctuant, cystic swellings which transilluminate and are readily palpable separate from the body of the testis are epididymal cysts and do not usually need further investigation.
- These can readily be distinguished from testicular tumours which arise from the testis.
- Spermatocele. There is no way clinically to differentiate between a cyst of the epididymis and a spermatocele. They can be differentiated as sperm are present in the milky fluid aspirate of a spermatocele. Such a procedure is not recommended as differential diagnosis does not change management.
- Inflammatory thickening, either acute or chronic of the epididymis. Such swellings will not transilluminate.
- Hydroceles. These are collections of fluid surrounding the entire testicle.
- Varicoceles. These are dilated veins and have been described as feeling like 'a bag of worms'. They increase with increase in abdominal pressure (Valsalva manoeuvre).
- Other scrotal masses, particularly extratesticular scrotal masses. These are predominantly benign. Lipomas are the most common extratesticular tumours.
- Cystic fibrosis. Congenital absence of the vas deferens is the most common genital tract anomaly in cystic fibrosis (99% of patients). Epididymal cysts are common.
- Von Hippel-Lindau disease. Along with other more significant manifestations of this syndrome, epididymal cysts are associated with the condition. It is a rare disease and important to recognise early.
- Maternal exposure to diethylstilbestrol.
- Polycystic kidney disease (autosomal dominant).
- Treatment is not usually necessary and explanation and advice are all that is usually required. Patients should be advised to seek medical advice if epididymal cysts become painful or suddenly start increasing in size.
- Surgical excision is recommended in children with intractable scrotal pain or if the cyst size does not seem to involute.
- Likewise excision may be offered to symptomatic adults. Percutaneous aspiration with instillation of sclerosant is another option but the sclerosant is often poorly tolerated and the recurrence rate is high.
Further reading and references
Niedzielski J, Miodek M, Krakos M; Epididymal cysts in childhood - conservative or surgical approach? Pol Przegl Chir. 2012 Aug84(8):406-10. doi: 10.2478/v10035-012-0068-2.
Valentino M, Bertolotto M, Ruggirello M, et al; Cystic lesions and scrotal fluid collections in adults: Ultrasound findings. J Ultrasound. 2011 Dec14(4):208-15. doi: 10.1016/j.jus.2011.10.008. Epub 2011 Nov 4.
Walsh TJ, Seeger KT, Turek PJ; Spermatoceles in adults: when does size matter? Arch Androl. 2007 Nov-Dec53(6):345-8.
Patel NG, Rajagopalan A, Shrotri NS; Scrotal liposarcoma - a rare extratesticular tumour. JRSM Short Rep. 2011 Dec2(12):93. doi: 10.1258/shorts.2011.011064. Epub 2011 Dec 6.
Lee JC, Bhatt S, Dogra VS; Imaging of the epididymis. Ultrasound Q. 2008 Mar24(1):3-16.
Blau H, Freud E, Mussaffi H, et al; Urogenital abnormalities in male children with cystic fibrosis. Arch Dis Child. 2002 Aug87(2):135-8.
Frantzen C, Links TP, Giles RH; Von Hippel-Lindau Disease
Palmer JR, Herbst AL, Noller KL, et al; Urogenital abnormalities in men exposed to diethylstilbestrol in utero: a cohort study. Environ Health. 2009 Aug 188:37. doi: 10.1186/1476-069X-8-37.
Torra R, Sarquella J, Calabia J, et al; Prevalence of cysts in seminal tract and abnormal semen parameters in patients with autosomal dominant polycystic kidney disease. Clin J Am Soc Nephrol. 2008 May3(3):790-3. doi: 10.2215/CJN.05311107. Epub 2008 Mar 5.
Erikci V, Hosgor M, Aksoy N, et al; Management of epididymal cysts in childhood. J Pediatr Surg. 2013 Oct48(10):2153-6. doi: 10.1016/j.jpedsurg.2013.01.058.
Vissamsetti B et al; Diagnosis and treatment of benign scrotal swellings, Trends in Urology & Men's Health, Volume 2, Issue 3, 2011.
Erikci V, Hosgor M, Yildiz M, et al; Torsion of an epididymal cyst: a case report and review of the literature. Turk J Pediatr. 2013 Nov-Dec55(6):659-61.
Gunaydin G, Ozyurt C, Kocak I, et al; Anti-bacterial activity of the fluid contents of spermatoceles and epididymal cysts. Br J Urol. 1995 Jan75(1):68-70.