Digestive and Liver Disease 39 (2007) 693–697 Brief Clinical Observation Aggressive systemic mastocytosis complicated by protein-losing enteropathy U. Mickys a , A. Barakauskien˙ e a , C. De Wolf-Peeters b , K. Geboes b , G. De Hertogh b,* a National Center of Pathology, P. Baublio 5, LT-08406 Vilnius, Lithuania b Department of Morphology & Molecular Pathology, University Hospitals KULeuven, Minderbroedersstraat 12, 3000 Leuven, Belgium Received 5 January 2006; accepted 5 June 2006 Available online 14 July 2006 Abstract A 46-year-old woman was admitted to the hospital with complaints of chronic diarrhoea, vomiting and severe muscle weakness. Clinical examination showed a lethargic, malnourished, dehydrated patient with ascites and bilateral leg oedema. Laboratory evaluation revealed mild normochromic normocytic anaemia and severe hypoproteinaemia with hypoalbuminaemia. Upper gastrointestinal endoscopy showed a thickened, friable duodenal mucosa with multiple erosions. Colonoscopy revealed nodular, pseudopolypoid lesions with patchy erosions in the left hemicolon. Haematoxylin-eosin stained sections from biopsies of endoscopically abnormal bowel segments showed multi-focal aggregates of large, histiocyte-like cells with abundant pale cytoplasm in the lamina propria. These cells were negative on PAS, Ziehl-Neelsen, Giemsa and toluidine blue stains. Their immunophenotype was CD68 (+), c-kit/CD117 (+) and mast cell tryptase (+), which is consistent with mast cells. A trephine biopsy showed diffuse replacement of the bone marrow by atypical, monomorphic, frequently spindle-shaped mast cells. No associated haematopoietic malignancy was detected. The final diagnosis was aggressive systemic mastocytosis with involvement of the gastrointestinal tract complicated by protein-losing enteropathy. This association has not been reported previously. The patient has been treated with prednisolone and interferon-alpha and has since recovered. © 2006 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved. Keywords: Mastocytosis; Protein-losing enteropathies 1. Introduction Mastocytosis is a proliferation of mast cells and their sub- sequent accumulation in one or more organ systems. This haematopoietic disorder has diverse manifestations, ranging from benign skin lesions to highly aggressive neoplasms with multisystem involvement. In cutaneous mastocytosis (CM), the mast cell proliferation is confined to the skin; systemic mastocytosis (SM) is characterised by involvement of at least one extracutaneous organ, with or without evidence of skin infiltration. In SM patients, bone marrow involvement is almost always present. Other organs frequently involved are the spleen, lymph nodes, liver and gastrointestinal (GI) tract. * Corresponding author. Tel.: +32 16 33 65 84; fax: +32 16 33 65 48. E-mail address: gert.dehertogh@uz.kuleuven.ac.be (G. De Hertogh). GI manifestations may be due to the pharmacological effects of secreted mast cell mediators or to space occupancy by the increased mast cell burden itself. We report on an SM patient presenting with chronic watery diarrhoea and severe hypoproteinaemia with hypoal- buminaemia, suggesting histamine-mediated hypersecretion and protein-losing enteropathy secondary to mucosal infil- tration by mast cells. 2. Case report A 46-year-old Lithuanian woman was admitted to the Gastro-Enterology Department with complaints of chronic diarrhoea, vomiting and severe muscle weakness. Watery diarrhoea (up to six bowel movements a day) started 6 months before admission after a short course of antibiotics for a respi- 1590-8658/$30 © 2006 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.dld.2006.06.003