Proposed Criteria for Classification of Acute Myeloid Leukemia in Dogs and Cats

Abstract

Blood and bone marrow smears from 49 dogs and cats, believed to have myeloproliferative disorders (MPD), were examined by a panel of 10 clinical pathologists to develop proposals for classification of acute myeloid leukemia (AML) in these species. French-American-British (FAB) group and National Cancer Institute (NCI) workshop definitions and criteria developed for classification of AML in humans were adapted. Major modifications entailed revision of definitions of blast cells as applied to the dog and cat, broadening the scope of leukemia classification, and making provisions for differentiating erythremic myelosis and undifferentiated MPD. A consensus cytomorphologic diagnosis was reached in 39 (79.6%) cases comprising 26 of AML, 10 of myelodysplastic syndrome (MDS), and 3 of acute lymphoblastic leukemia (ALL). Diagnostic concordance for these diseases varied from 60 to 81% (mean 73.3 +/- 7.1%) and interobserver agreement ranged from 51.3 to 84.6% (mean 73.1 +/- 9.3%). Various subtypes of AML identified included Ml, M2, M4, M5a, M5b, and M6. Acute undifferentiated leukemia (AUL) was recognized as a specific entity. M3 was not encountered, but this subclass was retained as a diagnostic possibility. The designations M6Er and MDS-Er were introduced where the suffix "Er" indicated preponderance of erythroid component. Chief hematologic abnormalities included circulating blast cells in 98% of the cases, with 36.7% cases having>30% blast cells, and thrombocytopenia and anemia in approximately 86 to 88% of the cases. Bone marrow examination revealed panmyeloid dysplastic changes, particularly variable numbers of megaloblastoid rubriblasts and rubricytes in all AML subtypes and increased numbers of eosinophils in MDS. Cytochemical patterns of neutrophilic markers were evident in most cases of Ml and M2, while monocytic markers were primarily seen in M5a and M5b cases. It is proposed that well-prepared, Romanowsky-stained blood and bone marrow smears should be examined to determine blast cell types and percentages for cytomorphologic diagnosis of AML. Carefully selected areas of stained films presenting adequate cellular details should be used to count a minimum of 200 cells. In cases with borderline diagnosis, at least 500 cells should be counted. The identity of blast cells should be ascertained using appropriate cytochemical markers of neutrophilic, monocytic, and megakaryocytic differentiation. A blast cell count of > 30% in blood and/or bone marrow indicates AML or AUL, while a count of < 30% blasts in bone marrow suggests MDS, chronic myeloid leukemias, or even a leukemoid reaction. Myeloblasts, monoblasts, and megakaryoblasts comprise the blast cell count. The FAB approach with additional criteria should be used to distinguish AUL and various subtypes of AML (Ml to M7 and M6Er) and to differentiate MDS, MDS-ER, chronic myeloid leukemias, and leukemoid reaction. Bone marrow core biopsy and electron microscopy may be required to confirm the specific diagnosis. Immunophenotyping with lineage specific antibodies is i...

Feline Leukemia Virus in a Captive Bobcat

“…The total white blood cell count was 2.8 ϫ 10 3 l; neutrophils were 1.1 ϫ 10 3 l, and lymphocytes were 1.3 ϫ 10 3 l indicating leukopenia, neutropenia and lymphopenia when compared to published reference ranges (Fuller et al, 1985;Kocan et al, 1985;Heidt et al, 1988). In addition, there was a marked macrocytic nonregenerative anemia (PCV was 11%; MCV was 77, and reticulocytes were 0.5%) (Jain, 1986). The chemistry panel was unremarkable expect for mild hypokalemia, and elevations of alanine aminotransferase (ALT) (498 IU/L) and aspartate aminotransferase (AST) (509 IU/L) suggesting liver damage.…”

“…Tracheal washing revealed suppurative inflammation. A bone marrow aspirate of the iliac crest revealed myelodysplasia with erythroid predominance (Jain et al, 1991). The samples were of poor quality with hemodilution and no appreciable particles.…”

Aspectos epidemiológicos, clínicos, hematológicos e anatomopatológicos da leucemia eritroide aguda (LMA M6) em gatos

“…O método de inclusão dos casos neste estudo foi o diagnóstico definitivo de LMA M6 através de critérios da OMS para classificação dos tumores hematopoéticos, publicados em 2002 pelo Instituto de Patologia das Forças Armadas (AFIP) , e que tem como base os parâmetros estabelecidos em 1991 pelo Grupo de Estudos da Leucemia Animal (ALSG) da Sociedade Americana de Patologia Clínica Veterinária (Jain et al 1991 (Bain 1998). Assim, para ser diagnosticada LMA M6 foi necessário que no mielograma os gatos apresentassem: 1) no mínimo 50% das células nucleadas da medula óssea (CNMO) pertencentes ao compartimento eritroide; e 2) pelo menos 20%-30% do total de células nucleadas não eritroides da medula óssea (CNNEMO) correspondentes a mieloblastos; ou 3) pelo menos 20%-30% do total de CNMO correspondentes a rubriblastos.…”

“…Segundo o Grupo de Estudos Franco-Americano-Britânico (Grupo FAB) (Bennett et al 1976) e a Organização Mundial de Saú-de (OMS) (Jaffe et al 2001), que se baseia no Clinical Advisory Committee Meeting, ocorrido em Airlie House, Virginia, em Novembro de 1997(Harris et al 2000, leucemia eritroide aguda é classificada como uma forma de leucemia mieloide aguda (LMA M6) e subdividida em duas formas de apresentação clinicopatológicas: LMA M6A, mais frequentemente descrita em humanos (Valli 2007a), e LMA M6B, muito mais comumente relatada em animais, principalmente em camundongos (Ney & D' Andrea 2000, Moreau-Gachelin 2006 e gatos (Jain et al 1991, Valli 2007a, e raramente em cães (Anderson & Johnson 1962, Groulade & Guillon 1967, Liu & Carb 1968, Tolle et al 1977, bovinos (Watanabe et al 1998), chimpanzés (McClure et al 1974) e ratos (Groulade & Guillon 1967, Bird & Huggins 1971. A primeira, também denominada de eritroleucemia, consiste em um neoplasma bilinhagem, que envolve mieloblastos e eritroblastos (Bennett et al 1976, Jain et al 1991, Harris et al 2000.…”

“…A primeira, também denominada de eritroleucemia, consiste em um neoplasma bilinhagem, que envolve mieloblastos e eritroblastos (Bennett et al 1976, Jain et al 1991, Harris et al 2000. A segunda, também chamada mielose eritrêmica (Bennett et al 1976, Valli 2007a, leucemia eritroide pura (Harris et al 2000, Jaffe et al 2001, eritroleucemia com predominância eritroide (Jaffe et al 2001), LMA M6Er (Jain et al 1991) e eritremia aguda (Jarret & MacKey 1974), é um distúrbio que afeta unicamente a linhagem eritroide (Bennett et al 1976, Jain et al 1991. Durante anos, em relação à LMA M6B, em medicina veterinária, tem-se dado preferência à denominação mielose eritrêmica (Jain 1986, Moulton & Harvey 1990, Jain 1993, Valli 2007a,b, Fighera & Graça 2010, já em medicina humana, as expressões leucemia eritroide pura e eritroleucemia com predominância eritroide são atualmente bem mais usuais (Jaffe et al 2001, Bain 2003.…”