Our findings suggest progression from the meningioangiomatosis to the malignant desmoplastic neoplasm through the occurrence of complex chromosomal abnormalities, and point to functional silencing of SMARCB1 in the dedifferentiation component.
We recently identified 3 mutually exclusive mechanisms of switch/sucrose nonfermentable (SWI/SNF) complex inactivation (BRG1 inactivation, INI1 inactivation or ARID1A/ARID1B co-inactivation) that are associated with histologic dedifferentiation in the majority of dedifferentiated endometrial carcinoma.
Distinct histologic patterns of anaplasia included increased mitotic activity in an otherwise classic PXA or associated with small cell, fibrillary, or epithelioid morphology, with loss of SMARCB1 expression in one case.
We recently reported that inactivation of BRG1 or INI1, core subunits of the switch/sucrose non-fermenting (SWI/SNF) complex, was the likely molecular event underlying dedifferentiation in about half of dedifferentiated carcinomas.