title: Marked hyperphosphatasemia associated with an acute leukemia in a Great Dane.
abstract: This is the report of a 5-year-old male neutered Great Dane with an extreme leukocytosis (544.9 × 10(9) cells/L; RI 5.2-13.9 × 10(9) cells/L) characterized by highly atypical round cells. Cellular morphologic features such as cytoplasmic membrane blebs, a high nuclear-to-cytoplasmic ratio, and nuclear indentations and irregularities and large nucleoli, as well as immunocytochemistry for CD3 and CD79, myeloperoxidase cytochemistry, and clonality testing were not conclusive for myeloid or lymphoid origin. Marked alkaline hyperphosphatasemia was present at the first visit (2783.0 U/L; RI 6-80.0 U/L), followed by a 5-fold increase (14,000 U/L) a week later, identified as being mostly contributed by the bone-ALP isoform (11,062 U/L; RI 0-30 U/L). In addition, the atypical leukocytes were strongly positive for cytoplasmic ALP activity. In vitro lysis of a heparin blood sample resulted in a 1.7-fold increase of ALP activity, supporting the origin of the hyperphosphatasemia at least in part from the leukemic cell population. To the authors' knowledge, this is a unique case of alkaline hyperphosphatasemia, due at least to a leukemic cell population producing a bone-ALP isoform, regardless of the exact nature of the leukemia.
authors.affiliation: Department of Pathology and Microbiology, Faculté de Médecine Vétérinaire, Université de Montréal, Saint Hyacinth, QC, Canada. fromentremi@gmail.com.
authors.forename: Rémi
authors.initials: R
authors.lastname: Froment
authors.affiliation: Department of Pathology and Microbiology, Faculté de Médecine Vétérinaire, Université de Montréal, Saint Hyacinth, QC, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Bédard
mesh_terms: D000208:Acute Disease; D000469:Alkaline Phosphatase / Q000097:blood*; D000818:Animals; D004283:Dog Diseases / Q000097:blood*; D004285:Dogs; D015470:Leukemia, Myeloid, Acute / Q000097:blood / Q000662:veterinary*; D007962:Leukocytes / Q000201:enzymology*; D008297:Male
chemical_list: D000469:Alkaline Phosphatase
keywords: ALP; Acute leukemia; canine; immunocytochemistry; lymphoproliferative; myeloproliferative