Endometrium Flashcards
(14 cards)
Key dates for dating of endometrium
Aglandular functionalis layer, suggestive of an underlying leiomyoma.
What to do in a biopsy for chronic endometritis
Scan on low power to look for IBD-like lymphoid inflammation of the endometrial glands.
Where you see it, zoom in and look around the stroma for plasma cells.
ISH for kappa/lambda can be helpful if you think it is there, but aren’t sure. Remember that placental site nodules or polyps can have plasma cells, but that doesn’t count for chronic endometritis - you need to see it in the background endometrium.
Grading of endometrial endometrioid adenocarcinoma
Grade 1: Less than 5% solid pattern
Grade 2: 5-50% solid pattern
Grade 3: >50% solid pattern
Squamous morules do not count as solid pattern.
Add 1 to the grade if there is severe cytologic atypia.
EIN criteria
- Crowding (More glands than stroma)
- Area of croweded glands >1mm in dimension
- Cytologic change from the background endometrium
Fat in an endometrial biopsy could mean. . .
. . . lipoleiomyoma versus perforation
Because it could indicate perforation, this is a critical value
Endometrial clear cell carcinoma
Consist of clear cells or hobnail cells in papillary, tubular, or solid growth patterns. May have a clear to eosinophilic cytology.
IHC: HNF1b+, AMACR+, NapsinA+, Ki67 high (about 50%). Usually negative for ER, but may be focally expressed.
Note: Generally IHC is not very helpful in differentiating clear cell carcinoma from other endometrial carcinomas - cytology is your friend here.
This entity is morphologically, immunophenotypically, and genetically identical to clear cell carcinoma of the cervix.
Endometrial serous carcinoma
High-grade anaplastic cells in complex papillary, glandular, or solid growth patterns. Necrosis and psammoma bodies are common.
Myometrial invasion is frequent, een more so than endometrioid, so make sure to sample well!
IHC: p53 mutant, p16+ (strong/diffuse), CK7+. WT1 may be positive in 30% of cases.
Molecular: TP53 mutation is a hallmark. 10% of cases show MMR deficiency.
Mesonephric-like adenocarcinoma
Histologically a tubulopapillary tumor with high N:C ratio that frequently shows a variety of architectures within the same mass.
IHC: GATA3+/TTF1+ in an invserse pattern. CD10 stains in a luminal pattern. ER/PR are usually negative.
Molecular: Mostly KRAS or NRAS mutated, sometimes CTNNB1 mutated.
Dedifferentiated endometrial carcinoma
Always consider other dedifferentiated high grade neoplasms in the differential: carcinosarcoma, SMARC4-deficient uterine sarcoma, and endometrial small cell carcinoma.
By definition, these tumors show loss of one of the SMARC components in the dedifferentiated component: INI1 loss, BRG1 loss, or combined ARID1A and ARID1B loss.
If there is dedifferentiated carcinoma present in a carcinosarcoma, the diagnosis is still carcinosarcoma.
Carcinosarcoma
Biphasic tumor with a component of any carcinoma and component of any sarcoma. Once you have a biphasic neoplasm, the specific carcinomatous components do not matter much for prognosis, even if a dedifferentiated component is present.
These are considered malignant epithelial tumors and behaves like a high grade carcinoma
Molecular subclassification should still be pursued. Report stains separately for the carcinomatous component and the sarcomatous component.
Mullerian adenosarcoma
Phyllodes tumor of the uterus - malignant stroma with a benign epithelial component.
To call ovulatory menstrual endometrium, you need. . .
. . . secretory glands AND stromal breakdown
The secretory glands are what tell you that ovulation ocurred. Otherwise, it could be drug induced or otherwise.
Main IHC marker for endometrioid adenocarcinoma
WT1+
