Postmenopausal endometrial fluid collections revisited: look at the doughnut rather than the hole.

Objective: To report 30 postmenopausal women and the thickness of the tissue surrounding an endometrial fluid collection seen on vaginal probe ultrasound.

Methods: During routine ultrasound-enhanced bimanual examination, nine postmenopausal women with unremarkable palpatory findings and no history of bleeding were found to have endometrial fluid collections. The patients were 9-24 years postmenopausal. All underwent prompt endometrial sampling. Each woman had some degree of cervical stenosis as judged by the operator. At curettage, all had scant tissue, which was reported by the pathologist as "inactive endometrium."

Results: Ultrasound scans on each patient were rereviewed, and it was found that the endometrium surrounding the fluid was uniformly 3 mm thick or less. Subsequently, 21 additional patients with small endometrial fluid collections have been seen. Eighteen of these had thin endometrium peripherally and were followed conservatively for 6-26 months. Six cases resolved and 12 remained unchanged. Three patients had a thickened heterogeneous endometrium peripheral to the fluid collection. In one, D&C was unsuccessful in two attempts because of cervical stenosis, and hysterectomy was performed. A 15-mm endometrial polyp was found. Two other patients with thickened endometrium surrounding the fluid had D&C, and hysteroscopy revealed simple hyperplasia without atypia. CONCLUSIONS. Normal atrophic postmenopausal endometrium in association with cervical stenosis can produce endometrial fluid collections, seen easily on vaginal probe ultrasound. If the endometrial tissue surrounding the fluid is thin (3 mm or less), the endometrium is invariably inactive and sampling is not necessary. If the peripheral endometrium is thicker than 3 mm, sampling is mandatory because the tissue cannot be expected to be invariably inactive and sampling is not necessary. If the peripheral endometrium is thicker than 3 mm, sampling is mandatory because the tissue cannot be expected to be inactive. Thus, the presence or amount of fluid is not as important as the thickness and character of the surrounding tissue.