Hypocellular marrow and extramedullary hematopoiesis in a dog: hematologic recovery after splenectomy

Nonregenerative anemia, poikilocytosis, thrombocytopenia, and splenomegaly were found in a 6-year-old dog. Marrow aspiration did not yield marrow particles, and microscopic examination of a marrow-core biopsy indicated hypocellular marrow. Marked extramedullary hematopoiesis was found in liver and spleen biopsy specimens. After splenectomy, the clinical and hematologic abnormalities resolved. The dog subsequently developed hemolytic anemia caused by Haemobartonella canis, which was resolved with oral tetracycline treatment. The dog remained healthy without recurrence of cytopenias or hypocellular marrow for 2 years after splenectomy. The clinical, hematologic, and microscopic findings in this dog were compatible with hypersplenism.