Description
Gastrointestinal stromal tumour (GIST) can show a multitude of histological appearances. Expression of CD34 and particularly CD117 are characteristic features of GIST but numerous other neoplasms are known to express either one of these markers. As a result of the above, there are several histological mimics of GIST; these include sarcomatoid carcinoma, vascular neoplasms, myofibroblastic neoplasms, solitary fibrous tumour, inflammatory fibroid polyp, dedifferentiated liposarcoma and melanoma. Because the diagnosis of GIST is becoming increasingly dependent on CD117 immunohistochemistry, great care is required in carrying out and interpreting this assay.
