Serum Anti-Müllerian Hormone Concentrations in Mares With Granulosa Cell Tumors Versus Other Ovarian Abnormalities

Recently, anti-Müllerian hormone (AMH) has been reported as a useful diagnostic marker for equine granulosa cell tumors (GCTs). The aim of this study was to examine and compare serum AMH and immunoreactive (ir)-inhibin concentrations in mares with ovarian abnormalities other than GCT compared to mares with known GCT in order to determine more useful diagnostic criteria. Mares with a possible GCT based upon history were subsequently classified into those with GCT confirmed by histopathology and mares with other abnormal ovaries (AO) without a GCT based on follow-up fertility information. Median concentrations of AMH were 72.6 ng/mL (quartiles: 20.6–458.5 ng/mL) in GCT and 0.70 ng/mL (0.26–1.44 ng/mL) in AO mares, and median concentrations of ir-inhibin were 2.36 ng/mL (1.65–3.79 ng/mL) in GCT versus 0.93 ng/mL (0.69–1.46 ng/mL) in AO mares. The cutoff values based on receiver operating characteristic (ROC) analysis were 4.70 ng/mL for AMH and 1.65 ng/mL for ir-inhibin. These cutoff values were slightly higher than the traditional value based on the normal reference range. The sensitivity, specificity, accuracy, and area under the ROC curve of AMH were higher than those of ir-inhibin. In conclusion, we demonstrated the diagnostic criterion of serum AMH concentration for equine GCT. Anti-Müllerian hormone is a more useful marker for diagnosis of equine GCT than ir-inhibin.