Clinicopathological and molecular characteristics of ovarian microcystic stromal tumors

ZHAI Cuijing; WANG Yuxiang; ZHANG Hongkai

doi:10.3969/j.issn.1007-8096.2025.07.020

Abstract：Objective Ovarian microcystic stromal tumor(MCST)is an extremely rare ovarian sex cord-stromal tumor.This study attempts to analyze its clinicopathological and molecular genetic characteristics in order to improve the current understanding of this tumor.Methods Four cases of microcystic stromal tumors and related clinical and pathological data were collected,and their morphological and molecular pathological characteristics were analyzed through immunohistochemical staining and PCR-Capillary Electrophoresis(PCR-CE)techniques.A literature review was also performed.Results Morphologically,the tumor cells exhibited small,round to oval nuclei with indistinct nucleoli.Most of the cytoplasm was acidophilic or vacuolated.Tumor cells form solid nests,sheets,or lobules with variably sized vacuolar cystic structures.The stroma was often myxoid with focal fibrosis.Immunohistochemical staining showed that in addition to positive nuclear staining for β-catenin,CD10,CyclinD1,WT1,and FOXL2 were also positive,while inhibin and Calretinin were negative.PCR-CE showed CTNNB1 mutations in 3 cases,and 1 case was a non-mutant subtype of CTNNB1(1/4).These patients underwent tumor resection or total hysterectomy with bilateral adnexectomy.Two patients with follow-up data had no recurrence,whereas recurrent cases were reported in the literature.Conclusion The diagnosis of microcystic stromal tumors often relies on pathological evaluation,incorporating comprehensive morphological features,immunohistochemical results,and/or molecular genetic characteristics.As findings in some reports are inconsistent,the mechanism of tumor occurrence still needs further exploration.Although most patients have a benign clinical course,some cases reported in the literature show metastasis and/or recurrence,or a family history of tumor syndrome.Therefore,long-term close follow-up is recommended,and clinicians should pay attention to the patients'family history.