Gastrointestinal stromal tumours: a clinico-pathological study

Hla OO, Pemasari Upali TELISINGHE, Ghazal KAFEEL, Prathibha Parampalli SUBRAHAMANYA, Sowmya Tatti RAJARAM

Department of Pathology, RIPAS Hospital Bandar Seri Begawan, Brunei Darussalam

ABSTRACT

Introduction: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal neoplasms of gastrointestinal tract. Histologically, it can be categorised into spindle cell, epithelioid cell or mixed spindle and epithelioid types. This study assesses the clinicopathological features of GISTs encountered in Brunei Darussalam. Material and Methods: The Department of Pathology registry from 1999 to 2009 was reviewed for cases of GISTs. There were 594 cases of gastrointestinal malignancies encountered during this period and GISTs accounted for 4.5% (n=27). Results: Men and women were equally affected and the ethnic breakdown consisted of Malay (70.4%), Chinese (14.8%), Filipino (11%3) and other races (3.7%). The clinical presentations were abdominal pain/mass (51%), upper gastrointestinal bleeds/melaena (30%8), dyspepsia/vomiting (11%) and anaemia (4%). One patient (4%) had GISTs as incidental finding on imaging study for other indication. The tumours were located in gastric (59.3%), small intestine (33.3%) and one case each for the colon/rectum (3.7%) and omentum (3.7%). The majority occurred between the fourth and seventh decade (range 16 to 83 years). Histologically, 66.7% were categorised as spindle cell, 18.5% epithelioid and 14.8% mixed cell types. On immunohistochemistry studies, 59% were positive for C-KIT (CD117), 66% for CD34, 48% co-expressed CD117 and CD34, 70% for Smooth Muscle Actin (SMA), 41% for S100 protein, 81% for Vimentin and 26% for Desmin. Based on tumour size and mitotic count, 3.7% was categorised as very low, 7.4% as low, 11% as intermediate and 77.8% high risk respectively. Conclusion: GISTs accounted for 4.5% of all GI malignancies and more than 70% were categorised as high risk. Accurate diagnosis is important as complete surgical resection is currently the first-line of therapy for resectable tumours. For unresectable disease targeted therapy with tyrosine kinase inhibitors is an option.

Keywords: Immunohistochemistry, interstitial cells of Cajal, leiomyosarcoma, proto-oncogene protein c-kit

Correspondence author: Hla OO, Department of Pathology, RIPAS Hospital, Bandar Seri Begawan BA 1710, Brunei Darussalam.

Tel: +673 2242424 Ext 6508, E mail: hlaoo39@yahoo.com

Brunei Int Med J. 2011; 7 (6): 314-320