Persistent nonregenerative anemia in a 4-year-old cat

A 4-year-old male neutered domestic shorthair cat was presented to The Ohio State University College of Veterinary Medicine for a 2-month history of severe weight loss, lethargy, anemia, and bilaterally hyperechoic kidneys with loss of corticomedullary distinction as reported by the referring veterinarian. Relevant initial laboratory results included severe non-regenerative normocytic hypochromic anemia, increased blood urea nitrogen, minimally concentrated urine, proteinuria, and an increased urine protein:creatinine ratio. Cytologic evaluation of a bone marrow aspirate revealed a markedly hypocellular marrow with abundant mucinous material. Gelatinous marrow transformation (GMT) was confirmed histologically by the presence of mucinous material in the bone marrow that stained positive for Alcian blue but negative for periodic acid-Schiff. The cat died despite repeated blood transfusions and supportive care. Gelatinous marrow transformation, immune complex-mediated membranoproliferative glomerulonephritis, and gastrointestinal hemorrhage were observed on autopsy and histology. It is likely that the development of GMT was secondary to chronic kidney disease (CKD) and that CKD, GMT, and gastrointestinal hemorrhage contributed to the cat's non-regenerative anemia.