Introduction: Development of renal cell carcinoma (RCC) is a life threatening complication of long- term haemodialysis. Studies have shown that approximately one third or more of patients on long-term haemodialysis of more than three years will develop acquired cystic kidney disease (ACKD), and 20- 50% of patients with ACKD, particularly with complex cysts of Bosniak types IIF, III and IV, may even- tually transform into RCC. This study looks at the incidence of haemodialysis related RCC in Brunei Da- russalam. Material and Methods: Cases of RCC registered in the Department of Pathology registry from January 2000 to December 2010 were identified and retrospectively reviewed. Results: A total number of 5,287 malignancies were reported during this period of which 74 were RCC, giving an overall incidence of 1.4%. Out of these 74 cases, 6.8% (n=5) was found to be RCC transformed from ACKD associated with long-term haemodialysis. There was a male preponderance (4:1), four Malay men and one Chinese lady with a median age of 51 years (37-66) at diagnosis. The duration of haemodialysis prior to the development of RCC ranged from 4 to 16 years. The common presenting signs and symp- toms were cystic mass in kidney 60% (n=3), haematuria and metastatic RCC in urinary bladder 20% (n=1), metastasis to the neck glands 20% (n=1). The right kidney was affected in four (80%) and one on the left (20%). Conclusion Our study showed that ACKD associated RCC accounted for 6.8% of all RCC, and the duration to RCC development ranged from four to 16 years. There was a preponderance in males. Radiological screening may need to be considered for patients at risk.

A 35-middle-aged female with history of recent travel to the Indian Subcontinent, presented with features of malabsorption. Blood chemistry revealed low serum albumin and low serum Vitamin B12 levels. Upper gastrointestinal endoscopy was done and was reported as normal. The duodenal biopsy sent for histopathologic examination and is shown (Panel). What is the diagnosis? Answer: refer to page 186

(Refer to page 164) Answer: Giardiasis. The slide shows duodenal biopsy with pear shaped protozoa of Giardia lamblia on the luminal surface of the villi. Giardia lamblia is a pear-shaped, flagellated protozoan that causes a wide variety of gastro-intestinal complaints. Giardia is possibly the most common parasite of humans worldwide and the second most common in the United States after pinworm.

Introduction:: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Histologically, it can be categorised into spindle cell, epithelioid cell or mixed spindle and epithelioid types. This study assesses the clinico-pathological 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. Results: : There were 594 cases of gastrointestinal malignancies encountered during this period and GISTs accounted for 4.5% (n=27). Men and women were equally affected and the ethnic breakdown consisted of Malay (70.4%), Chinese (14.8%), Filipino (11%) and other races (3.7%). The clinical presentations were abdominal pain/mass (51%), upper gastrointestinal bleeds/melaena (30%), dyspepsia/vomiting (11%) and anaemia (4%). One patient (4%) had GISTs as an incidental finding on imaging study for other indication. The tumours were located in the stomach (59.3%), small intestine (33.3%) and one case each involving 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.