JPC SYSTEMIC PATHOLOGY
MUSCULOSKELETAL SYSTEM
April 2019
M-T03

Signalment (JPC #2019268):  A mature, female New Zealand white rabbit

HISTORY:  This rabbit became depressed and emaciated.

HISTOPATHOLOGIC DESCRIPTION:  Bone:  Diffusely, thickening the epiphyseal, metaphyseal, and cortical bone, as well as the few remaining medullary trabeculae, are variably thick bands of lamellar bone (osteosclerosis) lined by wide seams of a deeply basophilic matrix with numerous embedded osteoblasts.  Layers of lamellar bone are separated by prominent irregular basophilic lines (cementing lines). Cementing lines are frequently smoothly contoured (resting lines) and rarely are scalloped (reversal lines).  There is a generalized absence of osteoclastic activity. The articular cartilage is either thin and irregular or thickened. Focally, the thickened cartilage contains variably sized clefts or is multifocally frayed with small clefts running perpendicular to the joint space (fibrillation). There are focal erosions with thinning of the underlying cartilage and irregularly clustered chondrocytes (chondrones). The articular cartilage is multifocally eosinophilic (loss of proteoglycans).  There are multifocal areas along the margin of the bone where the periosteum and adjacent bone is thickened, undulant, irregular and punctuated by remodeling and areas of basophilic matrix.

MORPHOLOGIC DIAGNOSIS: 

  1. Bone: Osteosclerosis, diffuse, moderate, with osteoblast hyperplasia and abundant basophilic osteoid matrix, New Zealand White rabbit, lagomorph.
  2. Articular cartilage: Degeneration, diffuse, moderate, with multifocal erosions, fibrillation. 

CONDITION:  Hypervitaminosis D

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Barthold SW, Griffey SM, Percy DH. Rabbit. In: Pathology of Laboratory Rodents and Rabbits. 4th ed. Ames, IA: Wiley Blackwell; 2016:313-314.
  2. Breshears MA, Confer AW. The urinary system. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:657.
  3. Gupta RC. Noncoagulant rodenticides. In: Gupta RC, ed. Veterinary Toxicology: Basic and Clinical Principles. New York City, NY: Academic Press; 2007: 552.
  4. Han S, Garner MM.Soft Tissue Mineralization in Captive 2-Toed Sloths. Vet Pathol. 2016 May;53(3):659-65.
  5. Holcombe H, Parry, N et al. Hypervitaminosis D and metastatic calcification in a colony of inbred strain 13 Guinea pigs, Cavia porcellus. Vet Pathol. 2015; 52:741-751.
  6. Rosol, T, Grone, A: Endocrine glands. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St. Louis, MO: Elsevier Limited;  2016:301-302.
  7. Thompson K: Bones and joints. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier Limited,; 2016: 89-90.
  8. Olson EJ, Carlson CS. Bones, joints, tendons, and ligaments. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:980.e1.


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