A 65-year-old postmenopausal woman presents with painless vaginal bleeding. She has no history of hormone replacement therapy. What is the most likely diagnosis?

Correct Answer: D. Endometrial carcinoma

Postmenopausal bleeding (PMB) is abnormal uterine bleeding occurring ≥12 months after the last menstrual period. In a 65-year-old woman with painless vaginal bleeding and no HRT history, endometrial carcinoma must be ruled out first. This is the cardinal red-flag presentation: PMB is malignant until proven otherwise. Endometrial cancer accounts for ~90% of malignancies presenting as PMB in India and globally. The absence of HRT (a risk factor for benign endometrial proliferation) and the patient's age (peak incidence 60–70 years) further elevate suspicion. Painless bleeding is typical of endometrial malignancy, which erodes vessels without causing uterine contractions. The diagnostic approach mandates endometrial sampling (Pipelle biopsy or D&C) to obtain tissue diagnosis. Even if imaging (TVS) shows a thin endometrium, histology is gold standard. Risk factors include obesity, diabetes, hypertension, and unopposed estrogen—common in Indian postmenopausal women. Per FIGO staging and Indian gynecological guidelines, any PMB warrants exclusion of malignancy before attributing it to benign causes.

Why the other options are wrong

A. Adenomyosis — Adenomyosis typically presents with dysmenorrhea and menorrhagia in reproductive-age women, not painless PMB. While adenomyosis can persist into perimenopause, it does not cause bleeding after menopause has been established for 12+ months. Adenomyosis is a benign condition and is not a diagnosis of exclusion in PMB—endometrial carcinoma must be ruled out first. B. Uterine fibroid — Fibroids cause heavy menstrual bleeding during reproductive years and may persist into early perimenopause, but they do not typically cause bleeding in established postmenopause (12+ months amenorrhea). If a postmenopausal woman with fibroids bleeds, malignancy must be excluded. Fibroids are benign and cannot explain PMB without concurrent endometrial pathology. C. Endometriosis — Endometriosis is a benign, estrogen-dependent condition that typically regresses after menopause due to loss of ovarian estrogen. It does not cause bleeding in established postmenopause. Endometriosis presents with dysmenorrhea and dyspareunia in reproductive-age women, not painless PMB in a 65-year-old.

High-Yield Facts

Mnemonics

PMB Red Flags (CANCER) Carcinoma (endometrial), Age >60, No HRT, Continuous bleeding, Endometrial thickening (>5 mm on TVS), Risk factors (obesity, DM, HTN). Use this to remember that PMB is cancer until proven otherwise. Benign PMB causes (FAD) Fibroids (early perimenopause only), Adenomyosis (rare in established menopause), Drug-related (HRT, tamoxifen). These are exceptions; always biopsy first.

NBE Trap

NBE may lure students into choosing fibroids or adenomyosis by emphasizing "common causes of abnormal uterine bleeding" without stressing that these are reproductive-age diagnoses. The trap is forgetting that PMB is a different clinical entity—the differential shifts entirely, and malignancy becomes the leading diagnosis.

Clinical Pearl

In Indian clinical practice, many postmenopausal women with PMB are initially treated empirically for "hormonal imbalance" or given HRT without biopsy—a dangerous delay. Always perform endometrial sampling in the first visit; a thin endometrium on TVS does not exclude cancer. Early diagnosis (stage IA) offers excellent prognosis with hysterectomy alone.

_Reference: DC Dutta's Textbook of Gynaecology (7th ed.), Ch. 11 (Abnormal Uterine Bleeding); Harrison's Principles of Internal Medicine, Ch. 50 (Gynecologic Malignancies)_