Testis & epididymis

Germ cell tumors

Epidermoid cyst

Topic Completed: 1 December 2012

Minor changes: 9 September 2020

Copyright: 2002-2021, PathologyOutlines.com, Inc.

PubMed Search: Epidermoid cyst [title] testis

Jennifer Gordetsky, M.D.
Sean R. Williamson, M.D.
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Cite this page: Gordetsky J, Williamson S. Epidermoid cyst. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisepidermoidcyst.html. Accessed December 6th, 2021.
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

Contributed by Debra L. Zynger, M.D.

Testicular epidermoid cyst

Cyst wall with adjacent normal seminiferous tubule

Lamellar keratin within the cyst

Stratified squamous epithelium with adjacent keratin

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
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