THE GIST OF IT: CASE REPORTS OF A GASTROINTESTINAL STROMAL TUMOUR AND A LEIOMYOMA OF THE ANORECTUM RAVI L. HUILGOL, CHRISTOPHER J. YOUNG AND MICHAEL J. SOLOMON Department of Colorectal Surgery, Royal Prince Alfred Hospital and University of Sydney, Sydney, New South Wales, Australia Key words: gastrointestinal neoplasms, leiomyoma, smooth muscle tumours. Abbreviations: GAN, gastrointestinal autonomic nerve tumours; GIST, gastrointestinal stromal tumours; GIT, gastrointesti- nal tract; ICC, interstitial cell of Cajal; NSE, neurone specific enolase; SMA, smooth muscle actin. INTRODUCTION Gastrointestinal stromal tumours (GIST) are an uncommon group of tumours of mesenchymal origin. They are postulated to arise from the interstitial cell of Cajal (ICC) or its precursor, the inter- stitial mesenchymal precursor cell. 1,2 The true incidence of these tumours is unknown. However, they are thought to be more ANZ J. Surg. 2003; 73: 167–169 CASE REPORT R. L. Huilgol MB BS; C. J. Young MB BS, FRACS; M. J. Solomon MB BS, FRACS. Correspondence: Mr C. Young, RPAH Medical Centre, Suite 419, 100 Car- illon Ave., Newtown 2042, NSW, Australia Email: cyoungnsw@aol.com Accepted for publication 9 November 2002.