Epididymal cyst

An epididymal cyst is the most common of epididymal masses.


Epididymal cysts have been reported in ~30% (range 20-40%) of asymptomatic individuals 5.


They are usually of lymphatic origin 2. Cysts contain clear serous fluid, lymphocytes, spermatozoa and debris.

Clinical presentation

Often manifests as a palpable mass. Approximately one-third of patients can be asymptomatic. It may be more prevalent in mountain bikers 3.

Radiographic features

They can be solitary or multiple with ~30% having more than one cyst 5.

  • cyst contents in uncomplicated cases are anechoic with no internal echoes
  • posterior acoustic enhancement may be seen
  • well defined anechoic lesions
  • larger cysts may contain septations
  • larger cyst may displace the testis which is the differentiating point from hydrocele which envelopes the testis

Differential diagnosis

Imaging differential considerations include

  • spermatocoele
    • usually has some internal echotexture, but may be indistinguishable from an epididymal cyst
    • epididymal cysts may arise throughout the epididymis, while spermatoceles almost always arise in the epididymal head 4
  • tunica vaginalis cyst
  • paratesticular abscess - will tend to show surrounding inflammatory changes; the clinical context is different
  • small hydrocoele to be differentiated from large epididymal cyst with septations

See also

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