"Oral Chondrosarcoma"
Tumor Tidbits  Volume 2, Number 6, April 2001
Editor:  Kevin A. Hahn, DVM, PhD, Dipl - ACVIM (Oncology) & Overall 
Nice Guy!

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ORAL CHONDROSARCOMA 

OVERVIEW: Oral chondrosarcoma is a malignant, cartilage-producing 
tumor with progressive local invasion of the surrounding tissues and 
has the following characteristics: Slowly progressive (months); 
Uncommon in dogs and cats; Highly invasive to surrounding bone; 
Metastasis rare; however, lung is a more common site than regional 
lymph node; Death usually secondary to local recurrence and cachexia; 
Patients are usually middle aged; More common in large-breed dogs; 
Most common location, maxilla. 

SIGNS: Excessive salivation; Halitosis; Bloody oral discharge; 
Dysphagia ; Weight loss; Cervical lymphadenopathy in a few patients; 
Facial deformity.

DIFFERENTIAL DIAGNOSIS: Osteosarcoma; Squamous cell carcinoma; 
Melanoma; Epulis; Abscess; Multilobular osteoma (i.e., chondroma 
rodens; appears radiographically as an osteoma arising from flat 
bones of the skull; highly metastatic; complete surgical excision 
uncommon); Osteoma; Multiple cartilaginous exostoses (i.e., 
osteochondromatosis; condition of growing dogs; cartilage-capped bony 
growths from the surface of flat bones; growth stops with skeletal 
maturity); Undifferentiated oral malignancy.

DIAGNOSTIC FINDINGS: Skull radiography to reveal bony lysis and 
proliferative changes; Survey thoracic radiography to detect 
pulmonary metastasis; A large, deep tissue biopsy (down to bone) 
required to sufficiently differentiate from osteosarcoma; Examination 
of cytologic preparations rarely diagnostic; Careful palpation of 
regional lymph nodes (i.e., mandibular and retropharyngeal) important.

LOCAL TREATMENT OPTIONS: Radical excision required (e.g., 
hemimaxillectomy) and well-tolerated by patient; margins of at least 
2 cm necessary; Metastatic behavior of most chondrosarcomas is low (< 
15%); survival improves when excisional margins are free of 
neoplastic cells; Soft foods recommended to prevent tumor ulceration 
and after radical oral excision; Inpatient radiotherapy results are 
unreported; most chondrosarcomas poorly responsive. 

CHEMOTHERAPY AND OTHER MEDICATIONS: Chemotherapy results are 
unreported; most chondrosarcomas poorly responsive. 

FOLLOW-UP: Repeat head and neck examination with survey thoracic 
radiography at 1, 2, 3, 6, 9, 12, 15, 18, and 24 months after 
definitive treatment; Most oral chondrosarcomas are locally invasive, 
but metastasis is low (< 15%).


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For additional information, try our web site at 
www.gcvs.com or call Dr. Hahn at 713-693-1166.