JPC SYSTEMIC PATHOLOGY
Musculoskeletal System
April 2019
M-N04

Signalment (JPC #1901223):  A male Doberman Pinscher

HISTORY:  This dog had a slowly developing swelling around the orbit and over the frontal bone. 

HISTOPATHOLOGIC DESCRIPTION:  Skull, orbit, and frontal bone (per contributor):  Extending to all borders is a multilobulated neoplasm composed of numerous variably sized, circular to oval to irregular islands of woven bone and well-differentiated cartilage, surrounded by spindle cells that form short irregular streams separated by narrow anastomosing and/or thick fibrovascular septa. Islands of cartilage contain chondrocytes within irregularly spaced lacunae surrounded by a basophilic cartilaginous matrix that occasionally mineralizes at the center. Trabeculae of immature woven bone have scalloped margins and are lined by osteoblasts and fewer osteoclasts within Howship’s lacunae, with numerous resting and reversal lines (remodeling) and haphazardly arranged osteocytes within lacunae. Immediately surrounding these islands of cartilage and bone are plump spindle cells (fibroblasts), with moderate amounts of pale eosinophilic cytoplasm and an oval nucleus, admixed with moderately dense fibrous connective tissue. In all cell populations there is mild anisocytosis and anisokaryosis and the mitotic count averages 0-1 per ten 400x HPF. There is scattered hemorrhage and mild edema.

MORPHOLOGIC DIAGNOSIS:  Skull, orbit, and frontal bone (per contributor):  Multilobular tumor of bone, Doberman Pinscher, canine.

CONDITION:  Multilobular tumor of bone (MTB)

SYNONYMS:  Chondroma rodens, multilobular osteosarcoma (MLO), multilobular osteochondrosarcoma, cartilage analogue of fibromatosis, calcifying aponeurotic fibroma, juvenile aponeurotic fibroma, multilobular osteoma, multilobular chondroma

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Olson EJ, Carlson CS. Bones, joints, tendons, and ligaments. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:995.
  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; 2016:117-118.
  3. Rissi DR. A retrospective study of skull base neoplasia in 42 dogs. J Vet Diagn Invest. 2015;27(6):743-748.


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