58° Congresso Nazionale SCIVAC: Oncologia veterinaria

58° Congresso Nazionale SCIVAC • Milano, 7-9 Marzo 2008 • Oncologia veterinaria - Alle soglie del III Millennio
USE OF FLOW CYTOMETRY IN THE CHARACTERIZATION
OF ACUTE MEGAKARYOBLASTIC LEUKEMIA (AML-M7)
IN A DOG
UTILIZZO DELLA CITOMETRIA A FLUSSO PER LA TIPIZZAZIONE
DI LEUCEMIA MEGACARIOBLASTICA ACUTA (AML-M7)
IN UN CANE
Fabio Valentini 1 Med Vet, MS; Silvia Tasca 2 Med Vet;
Valentina Caon 3 Med Vet
1,3
Libero Professionista (Roma)
2
Libero Professionista (Padova)
Acute megakaryoblastic leukemia is a rare form of myeloid leukemia first described
in 1931. Megakaryoblastic leukemia in human beings may occur as a
spontaneous disease or as a therapy-related acute leukemia. Cytogenetic abnormalities
of chromosome 21 have been associated with megakaryoblastic
leukemia in human beings. The simultaneous use of several differentiation
markers is required to diagnose this type of leukemia in people.
Megakaryoblastic leukemia is a rare myeloproliferative disorder in domestic
animals. Recently, thanks to the major availability of immunophenotypical
techniques the diagnosis is more accessible. The morphological evaluation
alone in fact has its limitations especially in the study of poorly differentiated
cells. Few reports have described AML-M7 in dogs with the use of flow cytometry.
This clinical case describes the utility of flow cytometry in the characterization
of acute megakaryoblastic leukemia (AML-M7) in a dog.
Clinical case. A 3-year-old, female spayed German shepherd was presented
for severe weakness, lethargy, anorexia and weight loss of several weeks duration.
Physical examination revealed pale mucous membrane, generalized
muscolar athrophy, tachycardia and mild hypothermia. Upon palpation, the
abdomen revealed a splenic enlargement. Initial diagnostic evaluation consisted
of a complete blood cell count (CBC), serum biochemical analysis and
urinalysis. Chest x-rays and abdominal ultrasound were performed as well.
CBC revealed severe anemia (Hct, 11,9%; reference range, 37 to 55%; Hb,
4,4 g/dl; reference range, 12,0 to 18, 0 g/dl), severe thrombocytopenia (9,000
platelets/µl; reference range, 150,000 to 500,000 platelets/µl) and mild leukopenia
(5,600 WBC/µl; reference range, 6,000 to 17,000 WBC/µl). Circulating
blast cells (30%) were detected. Bone marrow and spleen aspiration biopsy
was performed. The former revealed a good cellularity and adequate cell morphology;
all of the three hemopoietic cell lines (erithroyd, myeloid and megacaryocytic)
were almost completely substituted with large, variably sized
and round shaped blast cells, often bi- or multinucleated and with a marked
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