Non tumor

Topic Completed: 1 November 2011

Revised: 21 February 2019

Copyright: 2002-2017, PathologyOutlines.com, Inc.

PubMed search: endometriosis [title] uterus NOT tumor

Nat Pernick, M.D.
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Page views in 2019 to date: 6,812
Cite this page: Pernick N. Endometriosis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uterusendometriosis.html. Accessed August 23rd, 2019.
Definition / general
  • Endometrial tissue outside the uterus; closely related to adenomyosis
  • Women 20 - 30 years old, up to 10% of all women affected
  • Consists of functional layers of endometrium that go through menstrual changes, although is more proliferative than normal endometrium
  • Causes pain, infertility (1/3 of women are infertile)
  • Causes: regurgitation (retrograde menstruation), metaplasia and angiolymphatic dissemination (to lungs, nodes); metaplastic change of secondary Müllerian system represented by pelvic mesothelium
  • Sites: ovaries > uterine ligaments > rectovaginal septum > pelvic peritoneum > scar
  • Rarely in lymph nodes, usually with cuboidal epithelium, no stroma, limited to capsule and resembles tubal epithelium; call endosalpingiosis
  • Rarely has extensive intestinal tract involvement, resembling other intestinal diseases (Am J Surg Pathol 2001;25:445)
  • May undergo malignant transformation (Hum Pathol 2000;31:456)
  • Malignant tumors: endometrioid > clear cell, endometrial stromal sarcoma and MMMT
  • Organizing hemorrhage may cause adhesions, ovarian chocolate cysts
Diagrams / tables

Images hosted on other servers:

Chocolate cyst

Gross description
Gross images

Images hosted on other servers:

Small foci resembling "powder burns"

"Chocolate" cyst

Microscopic (histologic) description
  • Contains at least two of three features - endometrial glands, endometrial stroma and hemorrhage
  • May be a dense fibrous mass
  • May undergo mucinous metaplasia (also called endocervicosis or myxoid change)
  • Associated with perineurial invasion
  • May be associated with skeletal muscle regeneration (Am J Surg Pathol 2010;34:10)
Microscopic (histologic) images

Images hosted on other servers:

Focus of endometriosis

Endometrial glands and stroma in wall of GI tract

p63 expression

Multifocal polypoid
presenting as huge
pelvic masses

Cytology images

Images hosted on PathOut server:

Contributed by Dr. Carmen Luz:

Sheet of endo-
metrial epithelium
in FNA from
abdominal wall

Round endometrial epithelial group with slight atypia

Sheet of endometrial epithelium
adjacent to a group of endocervical
epithelium and endometrial stroma
from an endometrial direct cytology

Positive stains
Differential diagnosis
Additional references
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