Testis and epididymis
Nonneoplastic testicular lesions
Spermatocele

Author: Kenneth Iczkowski, M.D.
Editorial Board Member Review: Maria Tretiakova, M.D.
Deputy Editor Review: Debra Zynger, M.D.

Revised: 26 February 2018, last major update February 2018

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Testis [title] spermatocele

Cite this page: Iczkowski, K. Spermatocele. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testisspermatocele.html. Accessed August 17th, 2018.
Definition / general
  • Dilatation of the efferent ductules in the rete testis or head of epididymis
Epidemiology
  • All ages affected, but typically occur in 20 - 50 year old men
Etiology
  • Usually idiopathic but obstruction of outflow may play a role
Clinical features
  • Painless bulging
Radiology description
  • By ultrasound, cyst contents in uncomplicated cases are well defined, anechoic, with no internal echoes
  • Cyst may displace the testis if it is large
  • This is distinct from hydrocele, which envelops the testis but does not displace it
Radiology images

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Ultrasound images

Gross description
  • Arrives in laboratory as a collapsed membrane
Microscopic (histologic) description
  • Lined by single layer of cuboid to flat epithelium which is often ciliated
  • Thin wall of fibromuscular soft tissue
  • Cysts may be unilocular or multilocular; translucent
  • Lumen contains spermatozoa and proteinaceous fluid
  • Associated with foreign body giant cell reaction, cholesterol clefts
  • Epithelial lining may form a benign papilloma with fibromuscular cores lined by a single layer of columnar to cuboid epithelium with vacuolated cytoplasm
Microscopic (histologic) images

Images hosted on PathOut server:

Images contributed by Kenneth Iczkowski, M.D.
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Flattened cuboidal cells



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Flattened epithelial cells

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Numerous spermatozoa

Positive stains
Negative stains
Differential diagnosis
  • Hydrocele: originates between the parietal and visceral layers of tunica vaginalis; lining is mesothelial, lumen does not contain spermatozoa
    • Clinically distinguishable by aspiration cytology
  • Mesothelial cyst: usually originates from tunica vaginalis or tunica albuginea
  • Cystic dysplasia of rete testis: congenital lesion of newborns that is associated with ipsilateral renal agenesis
  • Sertoliform cystadenoma of rete testis: has tubules with or without lumina (Am J Surg Pathol 2018;42:141)
  • Simple cyst of rete testis: bulges into the testis proper
    • Common in men undergoing renal dialysis
    • Columnar epithelium, calcium oxalate crystals, fibrosis and giant cells
  • Tubular ectasia of rete testis: has numerous dilated canaliculi; can coexist with a spermatocele (Arch Ital Urol Androl 2015;87:5)
Board review question #1
    Spermatocele:

  1. Has a lining of mesothelial cells
  2. Is cytokeratin negative
  3. May have papillary infoldings with fibrovascular cores lined by vacuolated cuboidal or columnar cells
  4. Originates from the same membrane as hydrocele
Board review answer #1
C. May have papillary infoldings with fibrovascular cores lined by vacuolated cuboidal or columnar cells.

A. The lining is epithelial, not mesothelial.
B. Spermatocele is cytokeratin positive, unlike hydrocele.
D. Origin of spermatocele is from rete testis / head of epididymis epithelium, whereas hydrocele originates from the mesothelium of the tunica vaginalis.