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Epithelial tumors

Endometrial polyp

Reviewer: Jamie Shutter, M.D. (see Reviewers page)
Revised: 15 March 2012, last major update August 2011
Copyright: (c) 2002-2012, PathologyOutlines.com, Inc.

See also Polyp with atypical features


● Grossly pedunculated mass composed of cystically dilated glands with fibrous stroma and thick walled blood vessels

Clinical features

● Asymptomatic or associated with 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)
● Associated with tamoxifen therapy for breast cancer - may have severe atypia
● Note: must examine carefully for foci of serous carcinoma


● Excision is curative if (a) no hyperplasia, or (b) circumscribed foci of endometrial hyperplasia in polyp with no background hyperplasia

Gross description

● Multicystic cut surface; sessile or pedunculated

Gross images

Fundic polyps expand the uterine cavity

Polyp fills the uterine cavity

Partially cystic endometrial polyps

Small fundic polyp

Micro description (Histopathology)

● Polypoid shape, attenuated surface endometrium on 3 sides, cystic change, large thick walled blood vessels, fibrous stroma with spindled fibroblast-like cells, abundant extracellular connective tissue
● Glands are proliferative or inactive but usually peripheral and are typically angulated
● Rarely has atypical stromal cells

Micro images


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

Dilated thick walled vessels with proliferative type glands

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

Differential diagnosis

● Basalis endometrium
● Lower uterine segment endometrium
● Endometrial hyperplasia

Additional references

Mod Pathol 2000;13:309

End of Uterus > Epithelial tumors > Endometrial polyp

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