JPC SYSTEMIC PATHOLOGY
MUSCULOSKELETAL SYSTEM
April 2019
M-V03 (NP)

Signalment (JPC #1692713):  Chicken   

HISTORY:  This chicken had enlarged long bones of the wings and legs.

HISTOPATHOLOGIC DESCRIPTION:  Long bone, diaphysis:  Diffusely and circumferentially, the cortex is markedly thickened and the medullary cavity markedly reduced by an increase in both subperiosteal and endosteal woven bone (hyperostosis) that surrounds and separates a variably distinct layer of preexisting cortex composed of mature lamellar bone.  Hyperostotic areas are composed of irregular, often basophilic, variably thick trabeculae of immature woven bone containing numerous closely arranged, disorganized lacunae containing osteocytes.  There are few osteoclasts within Howship’s lacunae.  Trabeculae of woven bone lack normal bone marrow elements and are separated by loose fibromyxomatous connective tissue.  Multifocally the periosteum is moderately thickened by disorganized spindle cells that extend into and occasional are surrounded by underlying bone (fibrosis).  Large, irregular spaces within the outer third of the hyperostotic bone contain moderate amounts of hematopoietic marrow elements admixed with few loosely arranged spindle cells.

MORPHOLOGIC DIAGNOSIS:  Long bone, diaphysis:  Hyperostosis, subperiosteal and endosteal, diffuse, circumferential, severe (osteopetrosis), with multifocal periosteal thickening, chicken, avian.

ETIOLOGIC DIAGNOSIS:  Avian alpharetroviral osteopetrosis

CAUSE:  Avian leukosis virus (alpharetrovirus)

SYNONYMS:  Thick leg disease, marble bone disease

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTICS:

DIFFERENTIAL DIAGNOSIS:

Other osteopathies in birds:

COMPARATIVE PATHOLOGY:

Osteopetrosis:

Other Alpharetroviruses:

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. Philadelphia, PA: Elsevier; 2016:50-52, 91-94.
  2. Murakami T, Sassa Y. Pleomorphic malignant mesothelioma in a broiler breeder infection with avian leucosis virus subgroup J.  Jour Comp Pathol.  2018;160:50-55.
  3. Ojkic D, Brash ML, Jackwood MW, Shivaprasad HL. Viral diseases.  In: Boulianne M., ed. Avian Disease Manual. 7th Jacksonville, FL: American Association of Avian Pathologists; 2013:31-33, 37.
  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; 2017:973, 1005-1007.
  5. Shivaprasad HL. Miscellaneous diseases.  In: Boulianne M., ed. Avian Disease Manual. 7th Jacksonville, FL: American Association of Avian Pathologists; 2013:209-211,214,216.
  6. Shivaprasad HL. Nutritional diseases.  In: Boulianne M., ed. Avian Disease Manual. 7th Jacksonville, FL: American Association of Avian Pathologists; 2013:188-189.
  7. Yue Q, Yulong G, Liting Q, et al. Mutations in and expression of the tumor suppressor gene p53 in egg-type chickens infected with subgroup J avian leukosis virus. Vet Pathol. 2015;52(6):1052-1056.


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