Shari Owen
Center for Ob/Gyn, NY
Answer: Endometrial thickening would be coded with 621.3 (endometrial cystic heperplasia; hyperplasia [adenomatuous] [cystic] [glandular] of endometrium; hyperplastic endometritis) because the code includes hyperplasia of endometrium.
Hyperplasia is the abnormal multiplication or increase in the number of normal cells in normal arrangement in a tissue (Dorlands Illustrated Medical Dictionary).