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Published on: March 29, 2020
Cabot rings in a cat with myeloproliferative disease
Mizuki Fujimoto1, Masashi Takahashi1, Tatsuro Hifumi2
1Joint Faculty of Veterinary Medicine, Kagoshima University Veterinary Teaching Hospital, Kagoshima University, Kagoshima, Japan.
Insights
This case report details a cat with Cabot rings, a rare finding in red blood cells, indicating severe erythroid lineage defects. The cat
Area of Science:
- Veterinary Hematology
- Canine and Feline Pathology
- Erythropoiesis Research
Background:
- A 6-year-old cat presented with severe anemia and anorexia.
- Peripheral blood smears showed significant erythroid abnormalities, including Cabot rings.
Observation:
- Cabot rings, typically seen in human dyserythropoiesis, were observed in a feline patient.
- These rings persisted despite initial treatments for anemia.
Findings:
- The cat's condition worsened, with necropsy revealing neoplastic cells in bone marrow and organs.
- Immunohistochemistry confirmed neoplastic cells expressed CD71, an erythroid marker.
Implications:
- This is the first reported case of Cabot rings in a cat.
- Cabot rings in felines may suggest underlying bone marrow stress or dyserythropoiesis, potentially linked to neoplasia.
Abstract:
A 6-year-old spayed female Scottish Fold cat presented with lethargy and anorexia. A complete blood cell count indicated severe anemia and mild thrombocytopenia. Examination of peripheral blood smears revealed marked changes in the erythroid lineage, including the presence of basophilic stippling and Howell-Jolly bodies as well as an increase in nucleated erythrocytes, polychromatophils, ovalocytes, and schistocytes. Additionally, some erythrocytes contained a ring or figure-eight shaped structure known as a Cabot ring, which were especially observed in polychromatophilic erythrocytes. Hemolytic diseases (Mycoplasma infection and IMHA) were diagnostically excluded, and the cat was treated through prednisolone administration, whole blood transfusion, and administration of vitamins (K2 and B12); however, the anemia progressively worsened. Cabot rings were observed until Day 22 and subsequently disappeared as the number of nucleated RBCs increased, and the erythrocyte lineage shifted to immature population. On Day 42, peripheral blood examination revealed further left shifting and appearance of many rubriblasts. The patient died at home on Day 43. Necropsy revealed neoplastic cells infiltrating the bone marrow and other organs, which were immunopositive to CD71 which is an erythroid lineage marker. In humans, Cabot rings have been observed in megaloblastic anemia, lead poisoning, myelodysplastic syndrome, and myelofibrosis; further, they are thought to be related to stressed bone marrow and dyserythropoiesis. This is the first case report of a cat with Cabot rings, which are suggestive of defects in erythroid lineage production.
