Testis and epididymis
Germ cell tumors
Epidermoid cyst

Author: Jennifer Gordetsky, M.D., Sean Williamson, M.D. (see Authors page)

Revised: 5 June 2017, last major update December 2012

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PubMed Search: Epidermoid cyst [title] testis

Cite this page: Epidermoid cyst. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testisepidermoidcyst.html. Accessed November 21st, 2018.
Definition / general
Case reports
Gross description
  • Intraparenchymal lesion, usually adjacent to tunica albuginea, mean 2 cm, contains white grumous keratin debris
Microscopic (histologic) description
  • Cyst with keratinized squamous epithelial lining containing a granular cell layer, cyst filled with laminated keratin
  • Cyst rupture may cause granulomatous reaction
  • No adnexal structures, no other tissue types
  • Pilomatrixoma-like variant:
    • Adjacent testis does not show intratubular germ cell neoplasia, unclassified type (IGCNU)
    • Eosinophilic islands of "shadow" squamous epithelium with focal, peripheral calcification and ossification
    • The ghost-like cells are similar to the shadow cells of cutaneous pilomatrixoma (Am J Surg Pathol 2001;25:788)
Microscopic (histologic) images

Images hosted on PathOut server:

Images contributed by Debra Zynger, M.D. :

Testicular epidermoid cyst

Cyst wall with adjacent normal seminiferous tubule

Lamellar keratin within the cyst

Stratified squamous epithelium with adjacent keratin

Images hosted on other servers:

Epidermoid cyst - upper left

Compressed squamous epithelial lining

Microdissection to demonstrate LOH

Molecular / cytogenetics description
  • Isochromosome 12p and other overrepresentation of 12p are present in usual teratoma but not in epidermoid cyst (Clin Cancer Res 2006;12:5668)
Molecular / cytogenetics images

Images hosted on other servers:

Normal FISH for 12p

Differential diagnosis
  • Teratoma: usually postpubertal testis, IGCNU present, often atypia in teratomatous elements