Cases and Techniques Library (CTL) E223 Fat accumulation in enterocytes: a key to the diagnosis of abetalipoproteinemia or homozygous hypobetalipoproteinemia Fig. 3 Microscopic image showing vacuo- lization, especially on the top of the villi. Vacuolization causes a paler aspect because of fat dissolving during the process of embed- ding the tissue in par- affin wax (“empty” vacuoles instead of fat accumulation). Fig. 4 Negative peri- Fig. 1 A 20-year-old woman was referred by odic acid-Schiff staining her ophthalmologist to investigate the reason shows no microorgan- for her hypovitaminosis A and secondary night isms nor accumulation blindness. A macroscopic image taken during of glycogen, supporting gastroscopy shows a pale duodenal mucosa. the assumption that the vacuolization is due to lipid accumulation. level of detection). Her level of 25-hydroxy These findings suggested a diagnosis of Fig. 2 Videocapsule image illustrating the vitamin D appeared to be normal, but at either abetalipoproteinemia or homo- pale yet pronounced aspect of the villi. the time of her first admission, vitamin D zygous hypolipobetaproteinemia, disor- substitution had already been started. A ders that are caused by mutations in both This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. slightly raised alanine aminotransferase alleles of the microsomal triglycerides A 20-year-old woman was referred by her was also detected (33U/L). transfer protein (MTP) or in the APO-B ophthalmologist to investigate the reason Further work-up excluded cystic fibrosis, gene, respectively [1–2] This results in for her hypovitaminosis A and secondary exocrine pancreas insufficiency, and celiac the failure of APO B-100 synthesis in the night blindness. She had no other symp- disease. Gastroscopy revealed a very pale liver and APO B-48 synthesis in entero- toms of deficiencies in fat-soluble vita- duodenal mucosa; the villi, however, cytes, leading to fat accumulation in the mins, no abdominal complaints, and no could be easily recognized (●" Fig.1). small intestine. This diagnosis can be con- weight loss. Videocapsule endoscopy revealed a pale Laboratory examination revealed a defi- small bowel mucosa with extremely pro- ciency in vitamin A (<12µg/dL, normal nounced villi (●" Fig.2, ●" Video 1). Biop- Video 1 range 30–80) and vitamin E (<0.30 mg/dL, sies of the duodenal mucosa revealed normal range 0.5–1.8), a very low pro- areas of extended supranuclear vacuoliza- Videocapsule endoscopy in a 20-year-old woman thrombin time (30%), and very low levels tion of the cytoplasm in the villi. These suffering from hypovitaminosis A and secondary night blindness revealed a pale small-bowel mu- of cholesterol (30 mg/dL), triglycerides areas were interspersed with normal cosa with extremely pronounced villi. (4mg/dL), and LDL-cholesterol (below the areas (●" Fig.3 and●" Fig. 4). Desomer Lobke et al. Fat accumulation in enterocytes: a key to the diagnosis of abetalipoproteinemia or homozygous… Endoscopy 2015; 47: E223–E224 E224 Cases and Techniques Library (CTL) firmed by sequencing the MTP and APO-B Lobke Desomer, Martine De Vos, Arterioscler Thromb Vasc Biol 2013; 33: – genes [1]. Danny De Looze 2021 2025 3 Welty F. Hypobetalipoproteinemia and abe- This disorder can be treated by a low-fat Department of Gastroenterology and talipoproteinemia. Curr Opin Lipidol 2014; diet, supplementation of essential fatty Hepatology, Ghent University Hospital, 25: 161–168 acids, and high oral doses of fat-soluble Gent, Belgium vitamins [1]. Follow-up is necessary to Bibliography monitor potential ophthalmologic, neuro- DOI http://dx.doi.org/ logic, hematologic, and hepatologic com- 10.1055/s-0034-1391832 plications [1– 2]. Acknowledgment Endoscopy 2015; 47: E223–E224 This patient illustrates that the disorder is ! © Georg Thieme Verlag KG sometimes diagnosed in adulthood when Histologic images were kindly provided Stuttgart · New York the phenotype is mild [1–3]. The prog- by Stephanie Verschuere, MD, Pathology ISSN 0013-726X nosis is variable but adherence to the Department UZ Ghent. treatment regime can restore neurologi- Corresponding author cal function and prevent subsequent dis- Lobke Desomer, MD ease progression [1–2]. References Department of Gastroenterology 1 Lee J, Hegele R. Abetalipoproteinemia and De Pintelaan 185 homozygous hypobetalipoproteinemia: a Gent Endoscopy_UCTN_Code_CCL_1AB_2AZ_3AZ framework for diagnosis and management. 9000 J Inherit Metab Dis 2014; 37: 333–339 Belgium 2 Cefalù A, Pirruccello J, Noto D et al. A Competing interests: None Fax: +00-32-93324984 Novel APOB mutation identified by exome [email protected] sequencing cosegregates with steatosis, liver cancer, and hypocholesterolemia. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Desomer Lobke et al. Fat accumulation in enterocytes: a key to the diagnosis of abetalipoproteinemia or homozygous… Endoscopy 2015; 47: E223–E224.