1. Endometrial polyps
Dr Shaun Monagle
MBBS 1991

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

5. polyp

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 Note: Dilated thick-walled blood vessels
Stromal fibrosis (less than previous image)
Proliferative endometrial glands

9. Endometrial polyp (low power) features cystically dilated glands of various sizes and shapes

10. Endometrial polyp (high power) characteristic features of thick walled blood vessels in a fibrous core

11. 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

12. 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

13. 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

14. Adenosarcoma

15. Adenosarcoma note the cellular stroma

16. Adenosarcoma stromal cells condensing around cytologically benign glands

17. 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

18. References http://www.pathologyoutlines.com
Blaustein’s Pathology of the Female Genital Tract. 5th Edition. RJ Kurman. Springer-Verlag New York
Differential Diagnosis in Surgical Pathology. Haber, Gattuso, Spitz and David. Saunders, 2002
WHO Classification of Tumour. Pathology and Genetics. Tumours of the breast and female genital organs. Tavassoli and Devilee. IARC Press, 2003
Sternberg’s Diagnostic Surgical Pathology, 4th edition. SE Mills. Lippincott, Williams and Wilkins, 2004