Authors M. STRUYVE (1), M. FERRANTE (2), W. MEERSSEMAN (3), L. VAN OVERBEKE (4), D. CASSIMAN (3) / [1] University Hospital, Gasthuisberg, Leuven, Belgium, , Belgium, Gastroenterology, Hepatology and Endoscopy, [2] University Hospital Gasthuisberg, Leuven, Belgium, Gastroenterology, Hepatology and Endoscopy, [3] University Hospital Gasthuisberg, Leuven, Belgium, Metabolic Center, [4] AZ Sint Maarten, Mechelen, Belgium, Gastroenterology, Hepatology and Endoscopy Case Introduction: We report here clear endoscopic and histopathological images of the involvement of the colon in Tangier disease, which is rarely described in literature due to its curiosity. Aim: The aim of this abstract is to illustrate a rare case of a yellow to orange appearance of the colonic mucosa as seen in Tangier disease illustrated with the aid of clear endoscopic and histopathological images. Case report: A 51-year-old man was referred to the outpatient clinic for a routine colonoscopy because of abdominal discomfort in combination with loose stools suggestive for irritable bowel syndrome. His medical history consisted of pronounced atherosclerosis since young age and a tonsillectomy. Blood analysis revealed an abnormal lipid level with a low total cholesterol level of 80 mg/dl (normal < 190 mg/dl), an undetectable low (<3 mg/dl) HDL cholesterol level (normal > 40 mg/dl), a high triglycerides level of 807 mg/dl (normal < 150 mg/dl) and an undetectable low apolipoprotein A1 (< 0.20 g/L) (normal 1.04 – 2.02 g/L) and apolipoprotein A2. Colonoscopy revealed an irregular discoloration of the colonic mucosa with a yellow to orange appearance in combination with innumerable small yellow to brown dots with a scaly to cobblestone pattern and multiple polyps throughout the colon (figures 1 to 7). Histological analysis revealed colonic mucosa with focal aggregates of foam cells and foamy histiocytes in the lamina propria and submucosa (figure 8). Most polyps were hyperplastic deformed colonic mucosa with an excess of foamy histiocytes or so called xanthomateus lesions, other polyps were adenomatous lesions. Genetic testing showed a homozygous variant in the ABCA1-gene (c.5785G>T,p.(Val1929Phe)). The diagnosis of hypo-alphalipoproteinemia due to Tangier disease was made. Conclusion: Tangier disease is an inherent disorder of the lipid metabolism with an autosomal recessive transmission. It is a severe HDL deficiency syndrome leading to the accumulation of cholesterol in tissue macrophages and histiocytes. Due to mutations in the adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1-gene), which is a cell membrane protein responsible for the depletion of cholesterol out of the cells by the secretion of an excess of cholesterol from cells into the HDL metabolism, there is an extremely low HDL cholesterol level and accumulation of cholesterol in macrophages. The clinical presentation is often characterized by pronounced and complicated atherosclerosis at young age, peripheral neuropathy and typical yellow-orange tonsils. Abdominal complaints comparable to the symptoms seen in irritable bowel syndrome (abdominal discomfort, loose stools …) are described in patients with Tangier disease. Blood analysis shows a disturbed lipid profile with the absent of HDL cholesterol in combination with low total cholesterol, low LDL cholesterol, moderate elevated triglycerides levels and low apolipoprotein A1. We focused in this case report on the involvement of the colonic mucosa in Tangier disease that has a pathognomonic yellow to orange color in combination with small irregularities or dots. The presence of colonic polyps is often seen in Tangier disease and can histological either be hyperplastic colonic mucosa or even adenomatous lesions with aggregation of foam cells or foamy histiocytes. We report here clear endoscopic and histopathological images of the involvement of the colon in Tangier disease, which is rarely described in literature due to its curiosity.
