Diagnostic procedures for improving of the KIT (CD117) expressed allele burden for the liver metastases from uterus mast cell tumors: prognostic value of the metastatic pattern and tumor biology.

The activating KIT marker plays a central role in the pathogenesis, diagnosis, and targeted treatment of systemic mastocytosis (SM). Recent studies have identified the KIT (CD117) as a marker that distinguishes nonneoplastic from neoplastic mast cells in human systemic mastocytosis. In this study, we conclude that immunohistopathology assays for KIT staining pattern are useful complimentary tools for diagnosis and evaluation of prognosis in uterus mast cell tumor (MCT) metastasis to the liver in 10 patients. Uterine and hepatic cytology revealed mast cell neoplasia, which was confirmed as visceral mast cell tumor on postmortem examination. Histological changes of densely packed, poorly differentiated neoplastic mast cells, sheets of neoplastic round to pleomorphic cells that formed nonencapsulated nodules, high mitotic figures, necrosis, and fibrosis were found. In addition, eosinophils were scattered among the mast cells at the periphery of the nodules. These findings indicate tumors of high-grade malignancy with infiltrative cells resembling the uterus MCT in the intraparenchymal and periparenchymal areas of the liver. Immunohistochemically, tumors were positive for KIT. The histopathologic features coupled with the KIT immunoreactivity led to diagnosis of high-grade uterus MCTs. Taken together, these findings suggest that CD117 may play a critical role in early uterus MCT development and may be a stimulatory factor in grade 3 MCT. Therefore, the result has supported our hypothesis that there was an increased opportunity to observe a higher CD117 staining pattern in high-grade MCTs.