JPC SYSTEMIC PATHOLOGY
Musculoskeletal System
March 2019
M-M01 (NP)

Signalment (JPC #2314368):  3-day-old foal 

History:  This foal died of unknown causes.  This section is from a 2 cm raised nodule on the shaft of the radius.  Similar nodules were present on the ribs and other long bones.

HISTOPATHOLOGIC Description:  Radius (per contributor):  Elevating the periosteum are multiple 1 to 5 mm diameter nodules of  variably organized cartilage that extend from the periosteum into the underlying more normal cancellous bone and have a margin of hyaline cartilage with thin zones of chondrocyte proliferation, hypertrophy, and calcification undergoing endochondral ossification with formation of primary and secondary spongiosa progressing into bony trabeculae.  Within this cancellous bone are variably sized islands of cartilage (retained cartilage cores).   The surrounding trabeculae of lamellar bone are moderately thickened.  The marrow cavities contain sparse or absent hematopoietic cells. 

Morphologic Diagnosis:  Radius:  Osteochondromas, multiple (cartilaginous exostosis), breed unspecified, equine.

Condition:  Multiple cartilaginous exostoses (MCE)

SYNONYMS:  Osteochondroma (if single), osteochondromatosis (if multiple), hereditary multiple exostoses, osteocartilaginous exostoses, diaphyseal aclasis, metaphyseal aclasis, dyschondroplasia, hereditary deforming chondrodysplasia

General DISCUSSION:

Pathogenesis:

TYPICAL Clinical FINDINGS:

TYPICAL Gross FINDINGS:

TYPICAL LIGHT Microscopic FINDINGS:

Differential Diagnosis:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. De Brot S, Grau-Roma L, Vidal E, Segales J. Occurrence of osteochondromatosis (multiple cartilaginous exostoses) in a domestic pig (Sus scrofa domesticus). J Vet Diagn 2013;25(5):599-602.
  2. 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; 2016:54, 116-117.
  3. Olson EJ and Carlson CS. Bones, Joints, Tendons, and Ligaments. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th, St. Louis, MO: Elsevier; 2017:989-990.


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