Ovary tumor
Endometrioid tumors

Authors: Shahrzad Ehdaivand, M.D. (see Authors page)

Revised: 20 May 2016, last major update December 2012

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PubMed Search: Ovarian endometrioid tumor
Cite this page: Endometrioid tumors - general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/ovarytumorendometrioid.html. Accessed June 19th, 2018.
Definition / general
  • 10-20% of surface ovarian tumors, usually carcinomas
  • 15-40% are accompanied by endometrial carcinoma, but are considered independent primaries; often have a good prognosis
  • May represent:
    • Single clonal tumor with concordant genetic alterations (based on identical loss of homozygosity, identical PTEN mutation or sporadic microsatellite instability patterns) or
    • Single clonal tumor with genetic progression or
    • Double / triple clonal tumors (Hum Pathol 2002;33:421)
  • Presence of endometriosis in ovary usually means ovarian tumor is primary
  • Mixed tumors with endometrioid and serous / mucinous patterns also exist
  • Benign tumors are very rare (< 1% of all benign ovarian tumors), are often cystadenofibromas
Gross description
  • 40% bilateral, usually associated with extension beyond genital tract
Microscopic (histologic) description
  • Tubular glands resembling endometrium; usually foci of squamous differentiation; often arises in background of fibroma / adenofibroma
Microscopic (histologic) images

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Endometrioid polyp