The questions are depth of myometrial invasion (< or ≥ 50%), cervical stromal invasion, extension beyond the uterus and pelvic or para-aortic nodes — each changes the FIGO stage and the extent of surgery.
Orient first
- FIGO 2023 integrates histology and molecular class with anatomical extent (verify which edition your gynaecological oncologists use).
- The junctional zone and the subendometrial enhancement line define the inner myometrium; tumour is intermediate signal on T2 and restricts on DWI.
- Adenomyosis, fibroids and a thin myometrium in the elderly make depth assessment harder.
Acquire the study
- Pelvic MRI with an antiperistaltic agent: sagittal and double-oblique axial T2 (perpendicular to the endometrial cavity), DWI (b ≥ 800) with ADC, dynamic post-gadolinium T1 (sagittal, 2–3 min equilibrium phase); large-FOV T1/T2 to the renal hila for nodes.
The manoeuvre
- Sagittal T2: tumour within the cavity; the junctional zone and its disruption.
- Double-oblique axial T2 perpendicular to the cavity: depth of myometrial invasion — measure tumour depth and myometrial thickness in mm.
- DWI/ADC and the 2–3 min post-contrast phase: confirm the invasion margin (tumour enhances less than myometrium).
- Cervix on sagittal T2: stromal invasion (disrupted dark stromal ring) vs mucosal extension only.
- Serosa, adnexa, vagina, parametria; pelvic and para-aortic nodes up to the renal veins.
What confirms it
- Histologically proven endometrial carcinoma with MRI depth, cervical and extrauterine extent reported against the stated FIGO edition.
What licenses you to exclude it
- An intact junctional zone and subendometrial enhancement line exclude deep myometrial invasion on MRI.
The classic misread
- Overestimating depth where the tumour distends a thin myometrium or abuts adenomyosis.
- Assessing invasion on an axial plane that is oblique to the uterus.