A MALIGNANT GASTROINTESTINAL STROMAL TUMOR OF GALLBLADDER IMMUNOREACTIVE FOR PDGFRA AND NEGATIVE FOR CD 117 ANTIGEN (C-KIT)
GISTs of the gallbladder are extremely rare tumors. Only four malignant, two benign and one GIST-like tumor of the gall bladder have ever been described. The four malignant GISTs were all positive for CD 117 antigen (c-kit). We present for the first time a malignant gastrointestinal stromal tumor of the gallbladder, immunoreactive for platelet derived growth factor receptor alpha (PDGFRA) and negative for CD 117 antigen (c-KIT).