Response assessment of recurrent extragastrointestinal stromal tumor of the urinary bladder to imatinib: Findings on serial 18F-fluorodeoxyglucose positron emission tomography-computed tomography scans

Extragastrointestinal stromal tumors (EGISTs) are rare mesenchymal tumors occurring outside the gastrointestinal tracts that have similar histological and immunohistochemical characteristics similar to those of gastrointestinal stromal tumors. EGISTs involving the urinary bladder are extremely rare tumors with very few reports mentioned in the literature. We present a case of a 48-year-old man, known case of biopsy-proven EGIST of the urinary bladder that presented with recurrence after partial cystectomy and 18F-fluorodeoxyglucose positron emission tomography-computed tomography scans documenting the response assessment of the recurrent tumor to imatinib.