title: [A-leukemic caecal myeloid sarcoma: a difficult diagnosis].
abstract: Myeloid sarcoma is a malignant neoplasia composed of abnormal myeloid or monocytic cells, often localized in bones, but also rarely in extra-medullary sites such as lymph nodes, skin and soft tissue. We report a case of caecal myeloid sarcoma, diagnosed in a 60 year old woman who complained from abdominal pain and weight loss, in absence of any medullary disorder. Initially misdiagnosed as a B lymphoma because of a weak positivity for CD79a, the diagnosis of primitive caecal myeloid sarcoma was eventually established after further investigations showing a positivity for lysozyme and myeloperoxidase. This report of such a rare clinical and pathological presentation of a myeloid sarcoma underlines a difficult differential diagnosis for which adequate immunohistochemistry, including lysozyme and myeloperoxydase is mandatory.
authors.affiliation: Service d'Anatomie Pathologique, Cliniques universitaires UCL de Mont-Godinne, Yvoir, Belgique. marie-cecile.nollevaux@mont.ucl.ac.be
authors.forename: Marie-Cécile
authors.initials: MC
authors.lastname: Nollevaux
authors.forename: Monique
authors.initials: M
authors.lastname: Delos
authors.forename: Henri
authors.initials: H
authors.lastname: Noël
authors.forename: Anne
authors.initials: A
authors.lastname: Sonet
authors.forename: Alain
authors.initials: A
authors.lastname: Rosière
authors.forename: Ivan
authors.initials: I
authors.lastname: Théate
mesh_terms: D015746:Abdominal Pain; D015703:Antigens, CD / Q000032:analysis; D051925:CD79 Antigens; D002430:Cecal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007951:Leukemia, Myeloid / Q000175:diagnosis* / Q000473:pathology; D008875:Middle Aged; D009113:Muramidase / Q000032:analysis; D009195:Peroxidase / Q000032:analysis; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D015431:Weight Loss
chemical_list: D015703:Antigens, CD; D051925:CD79 Antigens; C497881:CD79A protein, human; D011947:Receptors, Antigen, B-Cell; D009195:Peroxidase; D009113:Muramidase