TY - JOUR T1 - Comparative Use of Napsin A and Glypican 3 to Distinguish Endometrial Clear Cell from Serous and Endometrioid Carcinomas JF - International Journal of Gynecologic Cancer JO - Int J Gynecol Cancer SP - 1318 LP - 1324 DO - 10.1097/IGC.0000000000001303 VL - 28 IS - 7 AU - Eirwen M. Miller AU - Joan Tymon-Rosario AU - Jaya Sunkara AU - Bryan E. Harmon AU - Rouzan G. Karabakhtsian AU - Akiva P. Novetsky Y1 - 2018/09/01 UR - http://ijgc.bmj.com/content/28/7/1318.abstract N2 - Objective Diagnosis of endometrial clear cell carcinomas is difficult owing to the low reproducibility of histological cell type in high-grade endometrial cancers. Recently, immunoreactivity for napsin A and glypican 3 has been reported in clear cell cancers. We sought to evaluate the use of napsin A and glypican 3 staining to distinguish clear cell carcinoma from other high-grade endometrial cancers.Methods/Materials Twenty cases of pure and mixed endometrial clear cell carcinoma were extracted from the 2000–2014 archival material in the Departments of Obstetrics & Gynecology and Pathology at Montefiore Medical Center and compared to serous and grade 3 endometrioid controls. Representative sections were stained with monoclonal antibodies to napsin A and glypican 3. Immunostains were independently reviewed by 2 pathologists to assess frequency and pattern of staining. Charts were reviewed for clinicopathologic and treatment data.Results Granular cytoplasmic positivity for napsin A was observed in 70% of endometrial clear cell carcinomas; only 25% showed cytoplasmic or membranous glypican 3 positivity. No serous or high-grade endometrioid tumors stained for either marker. No cases of clear cell carcinoma that stained negative for napsin A stained positive for glypican 3. No difference in the immunohistochemical profile was found between pure and mixed clear cell carcinomas and between early- and advanced-stage clear cell carcinomas.Conclusions Napsin A is a more sensitive marker for endometrial clear cell carcinoma than glypican 3. In histologically ambiguous cases, napsin A and glypican 3 may help distinguish clear cell carcinoma from other high-grade histologies. Further investigation of endometrial clear cell carcinoma is needed to identify additional diagnostic tools for this rare histology. Correlation of a unique immunohistochemical profile and clinical outcomes is necessary. ER -