[1243] Endometrial Stromal Sarcomas with Distinct Low and High-Grade Components: A Clinicopathologic Review of 11 Cases

Andrew P Sciallis, Gary L Keeney, William R Sukov, Debra A Bell. Mayo Clinic, Rochester, MN

Background: Endometrial stromal tumors (ESTs) represent a group of neoplasms composed of cells morphologically resembling proliferative-phase endometrial stroma. Cytogenetically, many of these tumors show a reciprocal balanced translocation between chromosomes 7 and 17 involving the JAZF-1 and JJAZ-1 genes. While ESTs includes endometrial stromal nodules and (low-grade) endometrial stromal sarcomas (ESS-LG), the existence and classification of a true high-grade endometrial stromal sarcoma has been debated. Cases showing both low and high-grade components are exceptionally rare, and the morphologic criteria for distinction are variable depending on the study. Herein we report 11 cases of high grade endometrial sarcoma with histologically distinct low and high-grade components.
Design: After obtaining IRB approval, we reviewed institutional and consultation cases interpreted as "endometrial stromal sarcoma" or ”undifferentiated stromal sarcoma” between 1994 and 2011. Only hysterectomy cases showing characteristic histologic ESS-LG features with a component sharply deviating from classic ESS-LG, or high grade tumors with a pattern of myometrial invasion similar to ESS-LG were included, yielding a total of 11 cases. The histologic and clinical features of each case were reviewed. Cytogenetics for t(7;17)(p15;q21) are pending.
Results: Each case showed an ESS-LG component, manifested as either an architectural pattern of tongue-like infiltration resembling ESS-LG or characteristic ESS-LG tumor cytology. In 11/11 cases, the high-grade component lost the typical infiltrative pattern of ESS-LG and formed necrotic sheets. The high-grade component showed increased eosinophilic cytoplasm in 11/11 cases but was otherwise cytologically heterogenous, featuring a combination of spindled (5/11), epithelioid (8/11), or pleomorphic (2/11) cells. The mean mitotic index in the high grade component was 45 mitoses/10hpf (range 21-84). Heterologous elements in the form of rhabdomyosarcoma were seen in 2/11 cases. In those patients with available clinical data, 8/8 patients presented with advanced disease and 7/8 died of disease.
Conclusions: We report 11 cases of a high-grade uterine sarcoma with a distinct ESS-LG component. Although the high-grade component was cytologically variable, they all featured increased cytoplasm, abundant tumor cell necrosis, and a high mitotic rate. The presence of both low and high-grade components, in conjunction with the aggressive behavior of these neoplasms, supports the existence of a true high-grade endometrial stromal sarcoma.
Category: Gynecologic & Obstetrics

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 184, Monday Morning


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