In a 28-year-old nulliparous woman with complaints of heavy menstrual bleeding and dysmenorrhea for 2 years, hysteroscopy reveals a solitary, smooth, pedunculated lesion protruding into the uterine cavity. What is the most common benign endometrial lesion causing abnormal uterine bleeding in this scenario?

Explanation

## Endometrial Polyp: Most Common Benign Endometrial Lesion ### Definition & Prevalence **Key Point:** Endometrial polyps are the most common benign lesion of the endometrium and are present in 10–20% of women evaluated for abnormal uterine bleeding. - Benign, localized proliferations of endometrial basalis and functionalis - Can be single or multiple - Typically pedunculated (as in this case) but may be sessile - Arise from the endometrial surface, often at the fundus or lateral walls ### Clinical Presentation - **Menorrhagia** (heavy menstrual bleeding) - **Metrorrhagia** (intermenstrual bleeding) - **Postmenopausal bleeding** (especially in perimenopausal/postmenopausal women) - **Dysmenorrhea** (secondary, due to uterine irritation) - Often asymptomatic and discovered incidentally ### Diagnostic Features | Feature | Endometrial Polyp | Submucosal Fibroid | Endometrial Hyperplasia | |---------|-------------------|-------------------|------------------------| | **Hysteroscopic appearance** | Smooth, pedunculated or sessile, tan/pink | Firm, irregular, may have cleft sign | Thickened, irregular endometrium | | **Sonographic appearance** | Echogenic, mobile, within cavity | Hypoechoic, distorts cavity | Diffuse thickening, heterogeneous | | **Histology** | Benign endometrial tissue with fibrovascular core | Smooth muscle with fibrous tissue | Glandular proliferation without atypia | | **Malignant potential** | <1% (rarely polyp cancer) | None (benign) | 1–3% (without atypia); 23–45% (with atypia) | | **Age of onset** | 40–60 years (can occur earlier) | 30–50 years | 40–60 years | **High-Yield:** The pedunculated, smooth appearance on hysteroscopy is pathognomonic for an endometrial polyp and distinguishes it from the irregular, firm appearance of a submucosal fibroid. ### Pathophysiology of Bleeding 1. Increased vascularity within the polyp 2. Abnormal endometrial angiogenesis (upregulation of VEGF) 3. Mechanical irritation during menstruation 4. Impaired hemostasis in polyp tissue **Clinical Pearl:** A solitary, pedunculated lesion on hysteroscopy is almost diagnostic of an endometrial polyp. Submucosal fibroids typically have a characteristic "cleft sign" (indentation at the junction with myometrium) and are firmer, more irregular. **Mnemonic:** **POLYP** — **P**edunculated, **O**ften **L**ocal, **Y**ellow-tan, **P**erfectly benign (mostly). ### Management - **Hysteroscopic polypectomy** is both diagnostic and therapeutic - Histopathology should be reviewed (rule out malignancy, though rare) - Recurrence rate: 15–30% if not completely removed [cite:Berek & Novak's Gynecology 15e Ch 16; FIGO Classification of AUB]