Original Article

Modern Pathology (2013) 26, 95–105; doi:10.1038/modpathol.2012.136; published online 24 August 2012

Endometrial sarcomas: an immunohistochemical and JAZF1 re-arrangement study in low-grade and undifferentiated tumors

Kiran Jakate1, Farshad Azimi1, Rola H Ali2, Cheng-Han Lee2, Blaise A Clarke1,3, Golnar Rasty1,3, Patricia A Shaw1,3, Nataliya Melnyk4, David G Huntsman4, Stephane Laframboise5 and Marjan Rouzbahman1,3

  1. 1Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
  2. 2Department of Pathology and Laboratory Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
  3. 3Department of Anatomical Pathology, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
  4. 4Centre for Translational and Applied Genomics (CTAG), BC Cancer Agency, Vancouver, British Columbia, Canada
  5. 5Department of Gynecologic Oncology, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada

Correspondence: Dr M Rouzbahman, MD, FRCPC, Toronto General Hospital, Room 11E215 11th floor, 200 Elizabeth Street, Toronto, ON M5G2C4, Canada. E-mail: marjan.rouzbahman@uhn.on.ca

Received 11 May 2012; Revised 4 July 2012; Accepted 4 July 2012
Advance online publication 24 August 2012

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Abstract

The current World Health Organization classification divides endometrial sarcomas into low-grade endometrial stromal sarcoma and undifferentiated endometrial sarcoma. Recent studies suggest undifferentiated endometrial sarcoma is a heterogeneous group and a subgroup with uniform nuclei is more akin to low-grade endometrial stromal sarcoma in terms of morphologic, immunohistochemical and genetic features. We classified endometrial sarcomas treated at our institution from 1998 to 2011 into low-grade endometrial stromal sarcoma and undifferentiated endometrial sarcoma, the latter being further categorized into a group with either uniform or pleomorphic nuclei. Morphological features, immunoprofile and fluorescence in situ hybridization rearrangements of JAZF1 and PHF1 genes were correlated with tumor category and outcome. A total of 40 cases were evaluated comprising 23 low-grade endometrial stromal sarcomas, 10 undifferentiated endometrial sarcomas with nuclear uniformity and 7 undifferentiated endometrial sarcomas with nuclear pleomorphism. Low-grade endometrial stromal sarcomas were more often estrogen and progesterone receptor positive (83%) compared with undifferentiated endometrial sarcoma with nuclear uniformity (10%) or with nuclear pleomorphism (0%) (P<0.001). Positivity for p53 was restricted to undifferentiated endometrial sarcomas with more frequent expression in the group with nuclear pleomorphism (57%) than with nuclear uniformity (10%) (P=0.06). Ki-67 proliferation index in >10% of tumor cells more frequent in undifferentiated endometrial sarcoma than low-grade endometrial stromal sarcoma (P=<0.001). JAZF1 rearrangement was detected in 32% of low-grade endometrial stromal sarcomas and in none of the undifferentiated sarcomas. Rearrangement of PHF1 was found in two patients, one with JAZF1−PHF1 fusion. There were no significant differences in clinical behavior between undifferentiated endometrial sarcoma with nuclear uniformity versus nuclear pleomorphism. In conclusion, we found undifferentiated endometrial sarcoma subtypes and low-grade endometrial stromal sarcoma have distinct immunohistochemical and cytogentic profiles. Our data do not show any difference in clinical behavior between subgroups in undifferentiated sarcomas.

Keywords:

endometrial sarcoma; immunohistochemistry; JAZF1; undifferentiated sarcoma