Review article: the biology, diagnosis and management of gastrointestinal stromal tumours.

BACKGROUND Gastrointestinal stromal tumours (GIST) are the most common mesenchymal tumours of the gastrointestinal tract with an increasing incidence. AIMS To review the biology, diagnosis and treatment of gastrointestinal stromal tumours. METHODS A PubMed search using the phrases 'Gastrointestinal stromal tumor', 'imatinib', 'c-kit'. RESULTS The diagnosis of GIST is established by histology supplemented by the immunohistochemical marker CD117, which is positive in 95% of cases. The most common site of the tumour is the stomach. Most GIST are benign with 20-30% malignant. Five-year survival for malignant GIST ranges between 35% and 65% and depends primarily on tumour size, mitotic index and location. The malignant behaviour of GIST is best assessed by invasion of adjacent structures and distant metastases. The gold standard for treatment is surgical resection. Imatinib, a tyrosine kinase inhibitor, is the primary therapy for unresectable, recurrent or metastatic disease. CONCLUSIONS Gastrointestinal stromal tumours are rare tumours of the gastrointestinal tract and they vary in presentation. When surgical resection is not achievable, imatinib is the treatment of choice.