A 58-year-old postmenopausal woman presents with abnormal uterine bleeding for 3 months. On examination, the uterus is enlarged and firm. Transvaginal ultrasound shows an endometrial thickness of 18 mm with heterogeneous echotexture. What is the investigation of choice to confirm the diagnosis of endometrial carcinoma?

Explanation

## Investigation of Choice for Endometrial Carcinoma Diagnosis ### Role of Endometrial Biopsy **Key Point:** Endometrial biopsy is the gold standard and investigation of choice for definitive diagnosis of endometrial carcinoma. It provides tissue confirmation and histological type, which is essential for staging and treatment planning. **High-Yield:** In any postmenopausal woman with abnormal uterine bleeding and thickened endometrium (>8 mm), endometrial biopsy is mandatory to rule out malignancy. ### Why Endometrial Biopsy? 1. **Tissue diagnosis** — Only histopathology can confirm malignancy and determine grade and type (adenocarcinoma, serous, clear cell, etc.) 2. **Outpatient procedure** — Can be done in clinic without anesthesia using Pipelle sampler or curette 3. **High sensitivity and specificity** — >90% sensitivity for detecting endometrial cancer 4. **Cost-effective** — Cheaper than imaging and provides definitive answer ### Diagnostic Algorithm for Postmenopausal Bleeding ```mermaid flowchart TD A[Postmenopausal bleeding]:::outcome --> B[Transvaginal ultrasound]:::action B --> C{Endometrial thickness?}:::decision C -->|< 4 mm| D[Reassure, follow-up]:::outcome C -->|4-8 mm| E[Clinical judgment]:::decision C -->|> 8 mm| F[Endometrial biopsy]:::action F --> G{Malignancy?}:::decision G -->|Yes| H[Staging & treatment]:::action G -->|No| I[Conservative management]:::outcome ``` **Clinical Pearl:** Even with normal-appearing endometrium on imaging, if clinical suspicion is high (persistent bleeding, risk factors), biopsy should not be deferred. [cite:Robbins 10e Ch 22]