2. Definition
• Benign localised overgrowth of endometrial
glands and stroma, covered by epithelium,
projecting above the adjacent epithelium
• Clonal lesions
– chromosome 6
3. Clinical features
• Prevalence ~ 24%
• More common in women > 40
• Present with
– intermenstrual or post-menopausal bleeding
– Infertility
– Persistent bleeding following curettage
• Common association with Tamoxifen use
4. Pathological findings
• Sessile or pedunculated
• Size: 1mm and beyond – may fill the
endometrial cavity and project through the
cervical os
• May be multiple
• May originate anywhere, but most
commonly fundus
6. Histopathology
• Irregularly outlined glands that may be out of phase with
endometrium
• Fibrovascular stalk or fibrous stroma with numerous thick
walled vessels
• Metaplastic epithelium particularly squamous may be
present
• Those in the lower uterine segment may contain
endocervical glands
• Mesenchymal component contains endometrial stroma,
fibrous tissue or smooth muscle.
• Absence of cytological atypia
• hyperplasia, carcinoma (any type) and carcinosarcoma
may involve or be entirely confined to a polyp
• endometrial intraepithelial carcinoma may be identified in
an atrophic polyp
7. • Benign polyp in a
hysterectomy specimen
– Note
• Endometrial epithelium
on three surfaces
• Dilated glands
• Fibrotic stroma
• Scattered dilated thick
walled blood vessels
8. Endometrial polyp (low power)
features cystically dilated glands of various sizes and shapes
9. Endometrial polyp (high power)
characteristic features of thick walled blood vessels in a fibrous core
10. Classification
• Morphologically diverse lesions that are difficult to
subclassify.
• Most are either hyperplastic, atrophic or functional.
– Hyperplastic
• resemble diffuse non polypoid endometrial hyperplasia
• no evidence that these have the same significance as diffuse hyperplasia, so
best to avoid the term hyperplastic in the diagnosis
– Atrophic
• low columnar or cuboidal cells lining cystically dilated glands
• typically in post-menopausal patients
– Functional
• resemble normal cycling endometrium
• relatively uncommon
11. Tamoxifen related polyps
• Larger, sessile with a honeycomb
appearance
• bizarre stellate shape of glands and frequent
epithelial and stromal metaplasias
• often periglandular stromal condensation
• malignant transformation in up to 3%
• interestingly the cytogenetic profile is
similar to non-iatrogenic lesions
12. Differential Diagnosis
• Endometrial hyperplasia
– diffuse process, majority of fragments in
curettage, absence of thick walled vessels
• polypoid endometrial carcinoma
– malignant epithelial cells
• adenofibroma
• adenosarcoma
– stromal cells cytologically atypical and
mitotically active
– stromal cells packed tightly around non
malignant glands
– leaf like pattern
16. Clinical behavior and treatment
• At most 5% of polyps contain carcinoma
• polyps may represent a marker of increased
cancer risk, but no evidence suggests they
are more likely to become cancer than the
adjacent endometium
• those containing atypical hyperplasia or
carcinoma should be treated as per similar
flat lesions
