obsolete_Leydig Cell Tumor true UMLS:C0023601 A sex cord-stromal tumor occurring in the testis and rarely in the ovary. It is predominantly or completely composed of Leydig cells which may contain crystals of Reinke. In males it usually presents as a painless testicular enlargement and it may be associated with gynecomastia and decreased libido. The majority of the cases have a benign clinical course. Approximately 10% of the cases have a malignant clinical course and metastasize. In females it may be associated with androgenic manifestations and it follows a benign clinical course. Leydig cell tumor Editor notes: Adding an axiom to this to localize to leydig cell entails equivalence with testicular leydig cell tumor Leydig cell neoplasm interstitial cell tumor NCIT:C3188 MESH:D007984 DOID:2696 EFO:1000321 http://purl.obolibrary.org/obo/MONDO_0006266 Leydig cell tumor, undetermined interstitial cell neoplasm ICDO:8650/1 Replaced by Mondo term MONDO_0006266, with which this term was previously merged. Use: http://purl.obolibrary.org/obo/MONDO_0006266 3.88.0