Document Type : Case Report(s)
Authors
1 Department of Pathology, School of Medicine, Al-Zahra Hospital, Isfahan, Iran
2 Department of Pathology, Isfahan University of Medical Sciences, Isfahan, Iran
3 Shahid Beheshti Fertility Center, Department of Gynecology and Obstetrics/Anatomy, Isfahan University of Medical Sciences, Isfahan, Iran
Abstract
Sclerosing stromal tumor (SST), a rare benign sex cord–stromal neoplasm, predominantly affects young women. Although SST typically demonstrates low mitotic activity and an indolent clinical behavior, mitotically active variants and bilateral presentations are exceptionally uncommon and may closely mimic malignant ovarian tumors. This diagnostic overlap is further complicated when proliferation indices such as Ki-67 are markedly elevated.
We report the case of a young woman presenting with bilateral ovarian masses, both demonstrating classical morphologic features of SST yet exhibiting unusually high mitotic activity and a markedly elevated Ki-67 proliferation index. Histopathologic examination revealed pseudolobular architecture with alternating cellular and edematous areas, abundant thin-walled branching vasculature, and a mixed population of spindle and luteinized stromal cells. Immunohistochemical evaluation showed strong positivity for inhibin and smooth muscle actin, with negative cytokeratin expression, findings supportive of SST despite the atypically high proliferative activity. No nuclear atypia, tumor necrosis, or other features suggestive of malignancy were identified.
This case underscores the importance of comprehensive clinicopathologic and immunohistochemical correlation in distinguishing mitotically active SST from malignant ovarian neoplasms. Awareness of these rare, benign variants is essential to avoid overdiagnosis and prevent unnecessary radical surgery, particularly in young women in whom fertility preservation is critical.
Highlights
Maryam Derakhshan (google scholar)
Elham Omidi (google scholar)
Keywords
- Case report
- Ovarian neoplasms
- Sex cord-gonadal stromal tumors
- Cell proliferation
- Immunohistochemistry
Main Subjects
Please cite this article as: Derakhshan M, Hadipour P, Derakhshan M, Omidi E. Bilateral mitotically active sclerosing stromal tumor of the ovaries: a rare case report. Middle East J Cancer. 2026: in press. doi: 10.30476/mejc.2026.103736.2171.
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