redo a biopsy

As imatinib Is targeting multiple receptor tyrosine kinases no oncologist will prescribe the drug without clearly identifying the target. You definitely need diagnosis proven by histology. Always in oncology.

This is a biopsy/pathology issue, not an oncology issue. If not C kit + imatinib may still be tried in Gist but must have diagnosis first. Repeat with additional cores x3

Thank you all for your kind response.