Diagnostic Value of Combined BCOR, Cyclin D1, and CD10 in Differentiating Endometrial Stromal Sarcoma From Other Uterine Spindle Cell Lesions.

Uterine spindle cell lesions share a dilemmatic overlapped features that needed to be addressed by the pathologist to reach a conclusive accurate diagnosis for its prognostic value and different management decisions. Usage of combined IHC panel can be an aiding guiding tool in this context. The aim of this study is to evaluate the diagnostic value of combined BCOR, Cyclin D1, and CD10 IHC panel in differentiating endometrial stromal sarcoma from other uterine spindle cell lesions. This study included 60 cases categorized into endometrial stromal sarcoma group (ESS) (12 cases high-grade endometrial stromal sarcoma [HGESS] and 18 cases low-grade endometrial stromal sarcoma [LGESS]), malignant uterine spindle cell lesions group (5 cases adenosarcoma [AS], 6 cases leiomyosarcoma [LS], 4 cases carcinosarcoma [CS]), and benign uterine lesions group (5 cases endometrial stromal nodule [ESN], 5 cases leiomyoma, and 5 cases adenomyosis). IHC staining procedure and evaluation for BCOR, Cyclin D1, and CD10 was performed on all studied cases. BCOR IHC staining was positive in all HGESS (12/12) of ESS group cases, with diffuse pattern in 75% of cases. BCOR-diffuse staining pattern was not recorded in any of LGESS (0/18), malignant mesenchymal lesions group (0/15), and also benign lesions group (0/15). Cyclin D1 positivity was observed only in HGESS cases, in parallel with positive-BCOR expression. On the contrary, CD10 was negatively expressed in all HGESS and positive in all LGESS, ESN, and adenomyosis cases. A specificity of 100% and sensitivity of 75% were recorded in differentiating HGESS from malignant mesenchymal lesions (including LMS, AS, and CS) and also HGESS from LGESS when using the combined panel BCOR +ve D /Cyclin D1 +ve / CD10 -ve , considering only the BCOR-diffuse staining pattern. In conclusion, BCOR +ve D /Cyclin D1 +ve /CD10 -ve as a combined panel is 100% specific and with lesser sensitivity in diagnosing HGESS as well as differentiating it from LGESS and other malignant uterine spindle cell lesions.