Abrupt onset of severe parkinsonism in a patient with metastatic gastrointestinal stromal tumor receiving treatment with avapritinib: A case report.

Gastrointestinal stromal tumors (GISTs) are tumors of the digestive tract. To date, there have been no neurological paraneoplastic syndromes or symptoms associated with metastatic GISTs. Tyrosine kinase inhibitors (TKIs) are the typical class of agents used in management of this malignancy.