Endometrial Sarcomas, How Many Categories Are Out There? A Tissue Microarray and Immunohistochemistry Study of 33 Cases
M Rouzbahman, G Rasty, F Azimi, BA Clarke, H Begley, PA Shaw. University Health Network, Toronto, ON, Canada
Background: The current WHO classification divides endometrial sarcomas into endometrial stromal sarcoma (ESS) representing low-grade tumors and undifferentiated endometrial sarcoma (UES). Yet it is not clear whether UESs are a heterogenous group or all represent undifferentiated tumors. Recent studies suggest that a subgroup of UES with uniform nuclei (UES-U) have similar morphology, immunoprofile or molecular genetics to low grade tumors. The objective of this study was to determine the morphology and immunoprofile of endometrial sarcomas in a series of cases from our institution and compare low grade and non low-grade sarcomas.
Design: 33 endometrial sarcomas with material available for study were retrieved in a 15 year period (1994- 2008). A tissue microarray (TMA) block, including duplicate 0.6 mm cores of each tumor, was prepared. The H&E slides of UES group were examined by 3 gynecologic pathologists separately and 4 cases were selected as having marked pleomorphic nuclei (UES-P). 9 cases were classified as UES-U. Immunohistochemistry for CD10, estrogen receptor (ER), progesterone receptor (PR), p53, p16, βCatenin, Ki67 was performed using standard techniques on TMA sections and protein expression was scored according to percentage tumor cells positive and staining intensity.
Results: The mean age of patients was ESS:51 and UES:61 yrs. Follow up was available in 10 of 13 UES and 15 of 20 ESS pateints. All UES-P, 3 of 6 UES-U and 13 of 15 ESS patients were alive with or without disease at the time of study. 1 UES-U and all UES-P patients had received adjuvant chemotherapy. 4 of 9 UES-U patients had received adjuvant radiotherapy.