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SMARCA4-deficient Undifferentiated Uterine Sarcoma: Clinicopathological Features of an Emerging Entity
Tripti Nakra1, Aanchal Kakkar1, Sandeep R Mathur1
1Department of Pathology, 28730All India Institute of Medical Sciences, New Delhi, India.
Abstract:
SMARCA4-deficient undifferentiated uterine sarcoma is a recently described molecularly defined entity among the subset of aggressive undifferentiated uterine tumors. Mutation in the SMARCA4 gene is a key driver alteration, as also seen in small cell carcinoma of ovary, hypercalcemic type (SCCOHT) and thoracic undifferentiated carcinoma. Limited number of cases of SMARCA4-deficient undifferentiated uterine sarcoma has been reported in literature. We hereby describe a case of this distinct entity in a 52-year-old woman. Histomorphological examination showed sheets of monomorphic epithelioid cells with a variable proportion of cells displaying rhabdoid features, brisk mitotic activity, and lymphovascular invasion. A panel of immunohistochemical markers was required to exclude the differential diagnoses. The tumor was microsatellite stable. Loss of SMARCA4 expression and intact expression of INI1 in tumor cells by immunohistochemistry (IHC) confirmed the diagnosis of SMARCA4- deficient undifferentiated uterine sarcoma. The patient had a rapidly progressive clinical course.
Insights
SMARCA4-deficient undifferentiated uterine sarcoma is a rare, aggressive uterine tumor. This case highlights its distinct histomorphology and the importance of molecular diagnosis for this aggressive cancer.
Area of Science:
- Gynecologic Oncology
- Molecular Pathology
- Cancer Genomics
Background:
- SMARCA4-deficient undifferentiated uterine sarcoma is a recently identified aggressive uterine tumor.
- SMARCA4 gene mutations are key drivers, also observed in small cell carcinoma of ovary, hypercalcemic type (SCCOHT) and thoracic undifferentiated carcinoma.
- Limited cases are reported, necessitating further clinical and pathological characterization.
Observation:
- A case of SMARCA4-deficient undifferentiated uterine sarcoma in a 52-year-old woman is presented.
- Histomorphology revealed sheets of monomorphic epithelioid cells with rhabdoid features, high mitotic activity, and lymphovascular invasion.
- Immunohistochemistry confirmed loss of SMARCA4 expression and intact INI1 expression, excluding other diagnoses.
Findings:
- The tumor was confirmed as SMARCA4-deficient undifferentiated uterine sarcoma.
- Immunohistochemical analysis was crucial for diagnosis and differential diagnosis.
- The patient experienced a rapidly progressive clinical course.
Implications:
- This case adds to the limited literature on SMARCA4-deficient undifferentiated uterine sarcoma.
- Accurate molecular and histological diagnosis is critical for understanding and managing this aggressive uterine malignancy.
- Further research is needed to elucidate the clinical behavior and therapeutic strategies for this distinct tumor entity.
