A thin and regular endometrium on ultrasound is very unlikely in patients with endometrial malignancy

To evaluate the clinical and sonographic features in patients with endometrial malignancy in whom endometrial thickness on ultrasound examination had been recorded in our database to be < 5 mm.

This was a retrospective observational study on 187 consecutive patients diagnosed with endometrial malignancy in whom an ultrasound evaluation of the endometrium had been performed in our institution. The characteristics of those patients presenting with an endometrial thickness < 5 mm were analyzed.

The median endometrial thickness was 15 mm: 12 mm for the women who underwent endometrial sampling before ultrasound examination vs. 17 mm in those who did not (P = 0.0086). In 13 women (6.9%), the endometrial thickness recorded in our database was < 5 mm. In 12 of these the measurement was compromised in some way: nine of these patients had undergone endometrial sampling (Pipelle biopsy in one and dilatation and curettage in eight patients) before the ultrasound examination, in two cases, focal malignant lesions were not included in the recorded endometrial thickness and in one, the endometrial thickness was visualized poorly due to myometrial distortion. In only one case was was the endometrium correctly measured to be < 5 mm; this woman had diffuse uterine and endometrial metastases of a breast cancer.

A thin and regular endometrial line is very reliable for the exclusion of endometrial carcinoma. The suspicion of focal lesions as well as incomplete visualization of the endometrium on sonography should be considered abnormal. Recently performed endometrial sampling makes measurement of the endometrial thickness unreliable.