Endometrioid tumors

Endometrioid borderline tumor

Topic Completed: 1 December 2012

Minor changes: 19 October 2020

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PubMed search: Ovarian endometrioid borderline tumor

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Cite this page: Ehdaivand S. Endometrioid borderline tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarytumorendoborderline.html. Accessed October 20th, 2021.
Definition / general
  • Rare (< 200 cases reported)
  • Mean age 55 years, range 28-86 years
  • 97% present with stage I disease
  • 36% associated with endometriosis
  • Typically no recurrent disease or metastasis on follow-up, even if intraepithelial carcinoma or microinvasion (Am J Surg Pathol 2003;27:1253, Am J Surg Pathol 2000;24:1465)
Microscopic (histologic) description
  • Composed of aggregates, glands or cysts of endometrioid-type epithelium that is atypical or cytologically malignant
  • May have architectural atypia including non-branching villous papillae, cribriform glands but lacks destructive stromal invasion, glandular confluence or stromal disappearance
  • Often has adenofibromatous pattern (47%) or squamous differentiation (47%)
  • May have foci of intraepithelial carcinoma (7%, high grade / grade 3 nuclei are large, pleomorphic with coarse chromatin or hypochromasia, large irregular nucleoli; also many mitotic figures; associated with villoglandular architecture or microinvasion)
  • Microinvasion if areas of invasion are 10 mm2 or less (7%)
Microscopic (histologic) images

AFIP images

With intraepithelial carcinoma, grade 1

glands separated
by stroma

Differential diagnosis
  • Atypical endometriosis: will have endometrial stroma
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