Skin nonmelanocytic tumor

Other tumors of skin


Last author update: 1 September 2012
Last staff update: 14 July 2021

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PubMed search: endometriosis [title] skin

Christopher S. Hale, M.D.
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Cite this page: Hale C. Endometriosis. website. Accessed April 14th, 2024.
Definition / general
  • This topic discusses features of cutaneous endometriosis only - a general discussion of endometriosis is found in the Ovary topic
  • Ectopic endometrial tissue, usually described in pelvic organs, but 0.5% - 1.0% of cases are cutaneous
  • Women of reproductive age, often due to iatrogenic seeding of umbilicus during C-section (Villar’s nodule) but may occur in almost any site
  • Carcinoma rarely arises in preexisting endometriosis
  • Women with endometriosis may have mildly increased risk of melanoma (Int J Epidemiol 2009;38:1143)
Case reports
  • Gonadotropin releasing hormone analogues
  • Excision
Gross description
  • Dark red to bluish nodule, may form cystic structure
Gross images

Images hosted on other servers:

Villar nodule

Microscopic (histologic) description
  • Endometrial glands, endometrial stroma and hemorrhage
  • May have marked decidual changes
Microscopic (histologic) images

Images hosted on other servers:

Endometriosis in periumbilical dermis

Various images

Positive stains
Negative stains
Differential diagnosis
  • Sweat gland tumor
  • Urachal duct cyst
  • Pyogenic granuloma
  • Hernia
  • Residual embryonic tissue
  • Primary or metastatic adenocarcinoma (Sister Joseph's nodule)
  • Cutaneous endosalpingiosis
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