Ute Bach (chair)

Nonproliferative and Proliferative Lesions of the Rat and Mouse Female Reproductive System: Revised INHAND Terms for Ovarian Sex Cord/Stromal Lesions

The nomenclature for the female reproductive system was originally published in 2014. After 10 years of practical use, the scientific community requested from the organ working group (OWG) a review of the terminology and criteria for diagnosing ovarian sex cord/stromal lesions. As a result, OWG proposes the use of “sex cord/stromal” as the base terminology for hyperplasia and tumors to better reflect their origin from the sex cord/stroma and make the terminology internally consistent. When no predominant cell type is present, these lesions should then be designated as mixed cell type (e.g., “hyperplasia, sex cord/stromal, mixed,” or “tumor, sex cord/stromal, mixed, benign”). When a clear, predominate cell type is present, the diagnosis should indicate that cell type (e.g., “sex cord/stromal, granulosa cell” or “sex cord/stromal, theca cell”). In the case of tumors, benign or malignant would be applied as appropriate. With these diagnostic revisions, the OWG for the female reproductive system attempts to provide clarification and refinement of criteria to be used for sex cord/stromal lesions.