Uterine fibroids are the most common of uterine benign tumors. Generally, the ultrasonic appearance of uterine fibroids is typical, and diagnosis is uncomplicated. However, the sonographic characteristics of fibroids undergoing cystic degeneration, and especially those of the submucous type, may be misleading. We present a series of submucous fluids with cystic degeneration in peri- and postmenopausal women showing a distinct sonographic “honeycomb” pattern erroneously diagnosed as endometrial hyperplasia. The correct diagnosis was established by hysteroscopy. © 1995 John Wiley & Sons, Inc.