Background: An 8-year retrospective study was conducted to evaluate the prevalence and the classification of canine bone marrow disorders in a clinical pathology service at a university referral hospital. Animals: Dogs evaluated for bone marrow disorders at a veterinary teaching hospital. Hypothesis: A better understanding of the spectrum and the prevalence of canine bone marrow disorders can be achieved with a multiyear retrospective study. Methods: Bone marrow aspirate smears, core biopsy specimens, and case records from 717 dogs were reviewed. Results: Bone marrow specimens were first categorized based on the presence or the absence of a primary bone marrow disorder. Nondysplastic and nonmalignant pathologic changes were placed into 14 subcategories. Frequently observed pathologic disorders included nonregenerative immune-mediated anemia, pure red cell aplasia, bone marrow necrosis, myelofibrosis, and hemophagocytic syndrome. Dysmyelopoiesis (n = 61) was subcategorized into myelodysplastic syndromes (n = 27), and congenital (n = 1) and secondary (n = 33) dysmyclopoiesis. One hundred twenty-six cases of neoplasia were divided into acute leukemia (n 46), chronic leukemia (n = 7), stage 5 malignant lymphoma (n = 28), multiple myeloma (n 25), malignant histiocytosis (n 11), metastatic mast-cell tumor (n = 3), sarcoma (n = 5), and carcinoma (n = 1). Conclusions and Clinical Importance: This study provides a general indication of the spectrum and the prevalence of canine bone marrow disorders at a referral center in North America.
