Gastrointestinal stromal tumours at the University of Nigeria Teaching Hospital Enugu, Nigeria: an immunohistochemical study of GIT mesenchymal tumours.

Mesenchymal tumours of the gastrointestinal tract (GIT) are uncommon. Recent progress in the understanding of the biology and origin of these tumours has led to their reclassification. A new subclass designated Gastrointestinal Stromal Tumours (GIST) is diagnosed based on the presence of a mutational over expression of c-kit protein that is thought to be critical in the pathogenesis of these tumours. This new class oftumours may form the majority of gastrointestinal mesenchymal tumours. Even though the diagnosis of GIST is mainly based on positive staining with CD117, a minority of tumours with histological characteristics of GIST are CD117 negative and are classified as CD117 negative GIST. In this first review of mesenchymal GIT tumours from Nigeria, we present 11 cases ofmesenchymal tumours of the gastrointestinal tract seen within a six-year period at our centre. Immunohistochemistry was performed on 7 of them in which histological appearances suggested GIST. Only two cases had all the criteria defined in the consensus conference on the diagnosis of GIST. Our findings, albeit in a very small sample, contrasts with what obtains in developed countries in the proportion of GIT mesenchymal tumours that are truly GIST. This raises a question to be answered on the true nature and proportion of gastrointestinal strumal tumours among GIT tumours in Nigerian patients.