West African Journal of Medicine

Deparments of Morbid Anatomy, College of Medicine, University of Lagos, P.M.B.12003, Surulere, Lagos, Nigeria Histopathology & Molecular Pathology, Leeds General Infirmary, Leeds, LS1 3EX, UK *Correspondence: Dr. Fatimah B. Abdulkareem, Dept of Morbid Anatomy, College of Medicine University of Lagos, P.M.B.12003, Surulere, Lagos, Nigeria E-mail: [email protected] Abbreviations: CD, cluster differentiation; GIST, gastrointestinal stromal tumour; GIT, gastrointestinal tract; GMT, Gastrointestinal mesenchymal tumour; SMA, smooth muscle antigen. ABSTRACT BACKGROUND: Gastrointestinal stromal tumour (GIST) represents only 1% of all malignant tumours of the gastrointestinal tract (GIT) but it is the most common gastrointestinal mesenchymal tumour (GMT) with majority arising from the stomach and small intestine. OBJECTIVE: To determine the prevalence of GIST using immunophenotypic characteristics. METHODS: Materials were formalin fixed paraffin embedded blocks of GMT diagnosed in Lagos Nigeria between January 1995 and February 2007. Sections were stained with CD117, CD34, SMA, S100 and Desmin antibodies at the research Laboratory of The Leeds General Infirmary, United Kingdom following standard procedure. RESULTS: Thirty-two cases of GMT (aged 10–78 years with a mean age of 46 and M: F=1.3:1) were analyzed. GIST accounted for 13 (40.6%), smooth muscle tumours 7(22%), vascular three(9.3%), de-differentiated liposarcoma two (6.2%), and unclassified (3%) of the GMT cases. Immuno-staining was not done for six cases of lipoma (18.7%). GISTpatients had a mean age of 45.4years with a M: F of 1.6:1; 54% was located in the stomach. Histologically, spindle cell type predominated accounting for 46% followed by mixed (31%) and epithelioid types (23%). Only 30.7% the GIST were suspected before immuno-staining. CONCLUSION: Gastrointestinal stromal tumour is the most common gastro-intestinal mesenchymal tumour in Lagos with a male preponderance. The most common site is the stomach. The immunophenotypic characteristics are comparable with gastrointestinal stromal tumours reported from other parts of the world. WAJM 2009; 28(6): 358–362.