What diagnostic tests should be ordered for a 59‑year‑old postmenopausal woman presenting with abnormal uterine bleeding?

Diagnostic Workup for Postmenopausal Abnormal Uterine Bleeding

Order transvaginal ultrasound combined with transabdominal imaging as the first-line test, followed immediately by endometrial biopsy using a Pipelle or Vabra device regardless of ultrasound findings, because postmenopausal bleeding carries a 90% association with endometrial cancer and requires tissue diagnosis. 1

Initial Diagnostic Approach

Transvaginal ultrasound (TVUS) is the recommended first imaging study to measure endometrial thickness and identify structural abnormalities such as polyps, fibroids, or focal lesions. 1, 2 The American College of Radiology assigns TVUS the highest appropriateness rating (7–9) for evaluating postmenopausal bleeding. 1

• Combine transvaginal with transabdominal ultrasound for complete pelvic assessment, and add color Doppler to detect vascularity within thickened endometrium, which improves specificity for pathology. 2
• An endometrial thickness ≤4 mm has a negative predictive value approaching 100% for endometrial cancer, but this threshold should not delay tissue sampling in a symptomatic 59-year-old woman. 2, 3
• Endometrial thickness ≥5 mm mandates endometrial sampling. 2

Endometrial Tissue Sampling

Office endometrial biopsy using Pipelle or Vabra is the definitive diagnostic step and should be performed even if ultrasound shows thin endometrium, because blind sampling has 99.6% and 97.1% sensitivity respectively for detecting carcinoma. 1

• Do not rely solely on ultrasound findings in a symptomatic postmenopausal woman—ultrasound cannot differentiate hyperplasia, polyps, and malignancy, and can only signal the need for tissue diagnosis. 1
• Office endometrial biopsy has a 10% false-negative rate, so if the initial sample is inadequate, non-diagnostic, or symptoms persist despite benign results, escalate immediately to hysteroscopy with directed biopsy or fractional D&C under anesthesia. 1, 4

When to Add Hysteroscopy

If TVUS reveals a focal endometrial lesion (polyp, submucous fibroid) or if blind biopsy is negative but bleeding persists, proceed to hysteroscopy with eye-directed biopsy. 1, 4

• Hysteroscopy has 98% sensitivity and 94% diagnostic accuracy for detecting endometrial pathology, significantly superior to ultrasound (87% accuracy) and blind sampling. 4
• Blind endometrial sampling can miss focal lesions such as polyps or localized carcinoma, making hysteroscopy the gold standard when focal abnormalities are suspected. 5, 4
• Saline infusion sonohysterography (SIS) should be performed when focal lesions are suspected or when standard TVUS cannot adequately visualize the endometrium; SIS has 96–100% sensitivity and 94–100% negative predictive value for endometrial pathology. 1, 2

Risk Stratification in This Patient

At age 59, this patient falls within the peak incidence window for endometrial cancer (>60 years). 1 Additional risk factors to assess include:

• Obesity (BMI ≥30) raises endometrial cancer risk 3–4-fold. 1
• Diabetes mellitus and hypertension are independent risk factors. 1
• Unopposed estrogen exposure (hormone replacement therapy without progestin, anovulation, tamoxifen use) significantly increases risk. 1
• Family history suggestive of Lynch syndrome (hereditary non-polyposis colorectal cancer) confers a 30–60% lifetime risk of endometrial cancer and warrants genetic testing. 1

Critical Pitfalls to Avoid

• Never accept a negative or inadequate endometrial biopsy as reassuring in a symptomatic postmenopausal woman—the 10% false-negative rate mandates escalation to hysteroscopy or D&C if bleeding persists. 1
• Do not delay tissue diagnosis by ordering only ultrasound; postmenopausal bleeding is endometrial cancer until proven otherwise. 1, 3
• Do not proceed to hysterectomy or endometrial ablation without first obtaining tissue diagnosis to exclude malignancy. 1, 2
• Pap smear is inadequate for evaluating postmenopausal bleeding—it screens for cervical cancer, not endometrial pathology. 1

Practical Algorithm

1. Order TVUS + transabdominal ultrasound with Doppler to measure endometrial thickness and assess for focal lesions. 1, 2
2. Perform office endometrial biopsy (Pipelle/Vabra) regardless of ultrasound findings in this symptomatic 59-year-old. 1
3. If biopsy is adequate and benign but bleeding persists, escalate to hysteroscopy with directed biopsy. 1, 4
4. If ultrasound shows focal lesion or biopsy is inadequate, proceed directly to hysteroscopy with directed biopsy. 1, 4
5. If atypical hyperplasia or carcinoma is confirmed, refer immediately to gynecologic oncology for surgical staging. 1