Epithelial tumors
Endometrial polyp

Author: Vijay Shankar, M.D. and Jamie Shutter, M.D. (see Authors page)

Revised: 29 April 2016, last major update April 2016

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Endometrial polyp [title]

Cite this page: Endometrial polyp. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uterusendopolyp.html. Accessed April 22nd, 2018.
Definition / general
  • Localized overgrowth of endometrial glands and stroma from the uterine cavity
  • Grossly pedunculated mass composed of cystically dilated glands with fibrous stroma and thick walled blood vessels
Essential features
  • Polypoid shape, attenuated surface endometrium on 3 sides
  • Cystic change
  • Large, thick walled blood vessels
  • Fibrous stroma with spindled fibroblast - like cells
  • Must be carefully examined to rule out malignancy
  • Can affect up to 25% of women
  • Most common site is the posterior wall of the uterine cavity, followed by anterior, lateral and uterotubal junction (Fertil Steril 2008;90:180)
  • Can be multiple
  • Represents hyperplastic response of normal endometrial tissue to unopposed estrogen
  • Patients with tamoxifen therapy are more prone to develop polyps
  • Late menopause, hormone replacement therapy and obesity increase risk of endometrial polyps (Maturitas 2005;50:231)
Clinical features
  • Asymptomatic or associated with abnormal vaginal bleeding
  • Glands are generally unresponsive to progesterone stimulation
  • Either hyperplastic (1/3 are associated with endometrial hyperplasia) or functional / secretory (grossly resembles a polyp but normal microscopic findings)
  • Cases associated with tamoxifen therapy for breast cancer may have severe atypia

  • Note: must examine carefully for foci of serous carcinoma
  • Hysteroscopic and radiological examination
  • Confirmed by histopathology
Prognostic factors
Case reports
  • Excision is curative if (a) no hyperplasia, or (b) circumscribed foci of endometrial hyperplasia in polyp with no background hyperplasia
  • Hysteroscopic removal or morsellation (Gynecol Obstet Fertil 2015;43:104)
Gross description
  • Commonly found in the posterior wall of the uterus (Fertil Steril 2008;90:180)
  • Small or large, single or multiple
  • Multicystic cut surface; sessile or pedunculated
Gross images

Images hosted on other servers:

Fundic polyps expand the uterine cavity

Polyp fills the uterine cavity

Partially cystic endometrial polyps

Small fundic polyp

Large endometrial polyp

Microscopic (histologic) description
Microscopic (histologic) images

Images hosted on PathOut servers:

These low-power photomicrographs show intact polypoid tissue fragments with dilated glands, fibrotic stroma and dilated thick-walled vessels

The difference in appearance at scanning magnification between the polyp in the upper part of the field and the adjacent nonpolypoid endometrium in the lower part is apparent

This polyp was identified in a curettage specimen from a menstruating patient. The intact nature of the polyp (above) compared with the fragmented menstrual endometrium below, is indicative of the manner in which polyps are often first recognized in a curettage specimen. In this polyp, the endometrial glands show secretory changes, which, however, are retarded relative to the phase of the menstrual cycle

This polyp is composed of relatively few glands, fibrotic stroma and dilated, thick-walled blood vessels

Dilated, thick-walled vessels are seen adjacent to a cystically dilated gland (top) lined by a single layer of flattened epithelium.

This polyp, in a pregnant woman, contains some endometrial glands that show gestational changes with Arias-Stella phenomenon, but without decidual change of the stroma

The glands show endocervical-type mucinous metaplasia. The stroma is diffusely fibrotic. More typical endometrial glands were seen elsewhere in this large polyp

This polyp contains complex hyperplasia with squamous metaplasia. The left side of the illustration shows a more typical endometrial polyp without hyperplasia or metaplasia

Images hosted on other servers:

Endometrial polyp

Granulomas in endometrial polyp

Microscopic examination of the polyp

Dilated thick walled vessels with proliferative type glands

Positive stains
Molecular / cytogenetics description
Differential diagnosis
Additional references