JPC SYSTEMIC PATHOLOGY
Musculoskeletal System
March 2019
M-M18

Signalment (JPC #1712510):  Dog

HISTORY:  None

HISTOPATHOLOGIC DESCRIPTION:  Bone, mandible (per contributor):  Diffusely the mandible is markedly thickened by a subperiosteal / endosteal proliferation of trabecular bone and the periosteum is thickened by a 1 to 5 mm thick band of dense, fibrous connective tissue (fibrosis) that obscures the cortex.  Secondary to the bone proliferation there is an undulant appearance to the bone surface.  Subperiosteal trabeculae are arranged perpendicular to the periosteum, are composed primarily of woven bone interspersed with rare areas of lamellar bone, are often moderately increased in thickness (osteosclerosis), and are often widely separated by variably dense areas of fibrosis.  Trabeculae contain many resting and reversal lines and are often lined by many osteoblasts and fewer osteoclasts within Howship’s lacunae (remodeling).  Within a focally extensive area, numerous neutrophils and admixed hemorrhage surround fragmented, subperiosteal trabeculae and extend into the adjacent fibrous connective tissue.  Multifocally, atrophic skeletal myofibers are entrapped within the overlying band of fibrosis. 

MORPHOLOGIC DIAGNOSIS:  Bone, mandible (per contributor):  Subperiosteal new bone growth, diffuse, moderate, with acute neutrophilic osteitis, multifocal osteosclerosis, marked periosteal fibrosis and skeletal muscle atrophy, breed unspecified, canine.

CONDITION:  Craniomandibular osteopathy

SYNONYM:  Lion jaw

GENERAL DISSCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Craig LE, Dittmer KE, Thompson KG. Bones and joints. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier; 2016:91-92.
  2. Pastor KF, Boulay JP, Schelling SH, Carpenter JL. Idiopathic hyperostosis of the calvaria in five young bullmastiffs. J Am Anim Hosp Assoc. 2000; 36(5):439-445.
  3. Thornburg LP. Infantile cortical hyperostosis (Caffey-Silverman syndrome). Animal model: Craniomandibular osteopathy in the canine. Am J Pathol. 1979; 95(2):575-578.
  4. 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: 1006, 1261.
  5. Woodard JC. Skeletal system. In: Jones TC, Hunt RD, King NW, eds. Veterinary Pathology, 6th ed. Baltimore, MD: Williams and Wilkins; 1997:913-914.


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