A 62-year-old woman with a history of obesity and diabetes mellitus presents with postmenopausal bleeding. Transvaginal ultrasound reveals an endometrial thickness of 22 mm with a heterogeneous mass projecting into the uterine cavity. Endometrial biopsy confirms grade 2 endometrial adenocarcinoma. Which investigation is most appropriate to assess myometrial invasion and determine surgical staging?

Explanation

## Staging Investigation for Endometrial Carcinoma ### Role of MRI Pelvis in Endometrial Cancer Staging **Key Point:** MRI pelvis with contrast is the most sensitive imaging modality for assessing myometrial invasion, cervical stromal involvement, and local extension—all critical for surgical staging of endometrial cancer. **High-Yield:** MRI is superior to CT for evaluating the relationship between tumor and myometrium due to excellent soft tissue contrast resolution. This information directly impacts surgical approach (simple vs. radical hysterectomy) and prognosis. ### Comparison of Staging Investigations | Investigation | Myometrial Assessment | Cervical Involvement | Distant Metastases | Use in EC | |---|---|---|---|---| | **MRI pelvis** | Excellent (T2 sequences) | Excellent | Limited | **Gold standard for local staging** | | CT abdomen/pelvis | Moderate | Moderate | Good | Metastatic workup, not local staging | | Hysteroscopy | Direct visualization | Possible | None | Therapeutic, not staging | | PET-CT | Poor for local | Poor | Excellent | Recurrent/metastatic disease | ### Staging Pathway for Endometrial Cancer ```mermaid flowchart TD A[Histologically confirmed EC]:::outcome --> B[MRI pelvis]:::action B --> C{Myometrial invasion?}:::decision C -->|< 50%| D[Stage IB]:::outcome C -->|≥ 50%| E[Stage IC]:::outcome B --> F{Cervical stromal involvement?}:::decision F -->|Yes| G[Stage II]:::outcome F -->|No| H[Stage I or higher]:::outcome A --> I[Chest X-ray/CT chest]:::action I --> J[Metastatic workup]:::outcome ``` **Clinical Pearl:** Depth of myometrial invasion is one of the most important prognostic factors in early-stage endometrial cancer. Invasion >50% of myometrial thickness significantly increases risk of lymph node metastases and recurrence. **Mnemonic:** **FIGO Staging of EC** — **F**ederation **I**nternationale **G**ynecologie **O**bstetrique. Stage I (confined to uterus), Stage II (cervical stromal involvement), Stage III (local/regional spread), Stage IV (distant metastases). [cite:Robbins 10e Ch 22]