Page 1292 - Clinical Small Animal Internal Medicine

1230 Section 11 Oncologic Disease

History and Clinical Signs are commonly found and a hallmark feature of MDS‐EB
VetBooks.ir The clinical signs of both MDS‐RC and MDS‐ER are is the presence of increased numbers of myeloblasts
(between 5% and 20% of total nucleated erythroid and
vague and commonly include lethargy and exercise intol­
erance. Physical exam generally reveals pale mucous myeloid cells).
membranes and an anemia‐related heart murmur.
Clinical signs of MDS‐EB tend to be more severe and Therapy/Prognosis
include depression, anorexia, fever, and diarrhea. These There is no standard treatment for primary MDS. In
patients commonly have a history of illness that pro­ humans, patients commonly receive no treatment
gresses over several months.
because they often do not have clinical signs. Supportive
care such as blood transfusions and antibiotics for infec­
Diagnosis tions is used as necessary. Growth factors can also be
used. In one case report of a dog with MDS‐ER, human
Evaluation of blood and/or bone marrow is needed for recombinant erythropoietin was used to treat profound
diagnosis of MDS. Because primary and secondary MDS anemia to promote terminal differentiation of dysplastic
cannot be consistently differentiated cytologically, a erythrocytes. The hematocrit increased and that patient
diagnosis of primary MDS should be made only if sec­ remained in remission for >30 months. Dogs with MDS‐
ondary causes have been ruled out. The most common RC and MDS‐ER can have prolonged survivals when
hematologic abnormalities in MDS‐RC and MDS‐ER are treated with chemotherapy (cyclophosphamide or cyto­
nonregenerative anemias without any evidence of throm­ sine arabinoside is most common) and supportive care.
bocytopenia or leukopenia. MDS‐ER differs from MDS‐ Patients with MDS‐EB can progress to AML and treat­
RC by characterization of marked erythroid hyperplasia ment has been less rewarding, with survival times of days
and the presence of >5% rubriblasts in the bone marrow. to months. For suitable dogs, allogeneic HSCT can be
Patients with MDS‐EB have moderate to severe nonre­ considered. The treatment and prognosis of secondary/
generative anemia with evidence of neutropenia and acquired MDS are dependent on the underlying cause.
thrombocytopenia. Dysplastic features in all cell lines

Further Reading

Comazzi, D, Gelain ME, Martini V, et al. the literature and goals for future investigation. Vet
Immunophenotype predicts survival time in dogs with Pathol 2011; 48: 182–97.
chronic lymphocytic leukemia. J Vet Intern Med 2011; Williams MJ, Avery AC, Lana SE, et al. Canine
25: 100–6. lymphoproliferative disease characterized by
Tasca, S, Carli E, Caldin M, et al. Hematologic lymphocytosis: immunophenotypic markers of
abnormalities and flow cytometric immunophenotyping prognosis. J Vet Intern Med 2008; 22: 596–601.
results in dogs with hematopoietic neoplasia: 210 cases Young KM, Vail DM. Hematopoietic tumors. In: Withrow
(2000–2006). Vet Clin Pathol 2009; 38(1): 2–12. SJ, Vail DM, Page RL, eds. Withrow and MacEwen’s
Uopperi, TA, Bienzle, D, Bernreuter DC, et al. Prognostic Small Animal Clinical Oncology, 5th edn. St Louis, MO:
markers for myeloid neoplasms: a comparative review of Saunders, 2013, pp. 653–65.