Dog, head: severe, diffuse, fibrous osteodystrophy (“big head disease”).
History: Labrador puppy, 21 weeks Diagnosis: Head: severe, diffuse, fibrous osteodystrophy (“big head disease”)Description: The face area of the skull, including upper and lower jaw, is enlarged. Diastemata of the upper jaw are widened and the teeth are irregular arranged. Comments: The puppy clinically showed reduced growth, swelling of the head, polyuria and azotemia. Both kidneys were shrunken and showed an irregular surface. Histology: Facial bones, ribs and almost all long bones showed a severe fibrous osteodystrophy. The kidney showed asynchronous differentiation of nephrons, immature glomeruli, persistent immature mesenchyme and proliferation of the tubular epithelium. The parathyroid gland was moderately hyperplastic. These findings are consistent with renal dysplasia, followed by secondary hyperparathyrodism and fibrous osteodystrophy (osteorenal syndrome).Picture by: Melanie Bothe, Department of Veterinary Pathology, Freie Universitaet Berlin, GermanyAuthor: Melanie Bothe, Department of Veterinary Pathology, Freie Universitaet Berlin, Germany