Figure 2.37 A large osteochondroma arising from the coronoid process occupied the infratemporal fossa. The tumor interferes with the zygoma and lateral wall of the maxilla.
- Benign neoplasm in the TMJ.
- TMJ osseous ankylosis.
- Medically the patient was healthy. The pain in the preauricular region is not stress related.
- There were no signs of dental infections and no suspicion of soft tissue tumors or inflammation.
- To rule out other disorders that cause limitation of mouth opening, CT examination was done.
- Tumor of the coronoid process (osteochondroma) was diagnosed after resection of the lesion.
- Resection of the tumor.
- The primary dentist treated the patient with physical therapy and NSAIDs, but the limitation of mouth opening was not due to TMD.
- CT or MRI images would be of great help for differential diagnosis of these kinds of disorders.
- Because of this being a benign tumor, prognosis is good after resection.
- Osteochondroma, sometimes called osteocartilagenous exostosis, is the most common benign tumor of bone. It represents 35% of all benign bone tumors.
- The clinical signs and symptoms do not distinguish this tumor from other slow-growing tumors or tumor-like masses of the condyle. In particular, it is difficult to distinguish from condylar hyperplasia.
- Histopathologically, the tumor contains trabecular bone with a rim of cartilage. The chondrocytes can form rows that are perpendicular to the surface of the lesion, and they may overlie a zone of endochondral ossification.
- Radiographically, the tumor usually shows a globular pattern with distorted condylar morphology, whereas in condylar hyperplasia the condylar head is simply symmetrically enlarged and the condylar neck is usually lengthened.
- If osteochondroma occurs on a condyle, a slowly developing asymmetry is associated with ipsilateral deviation of the chin and unilateral posterior open bite.
(Unni and Carrie, 2010)
Expanded DC/TMD criteria for Neoplasm in jaw, benign (Peck et al., 2014). Sensitivity and specificity have not been established.
- Neoplasms of the joint result from tissue proliferation with histologic characteristics, and may be benign (e.g., chondroma or osteochondroma) or malignant (e.g., primary or metastatic). They are uncommon but well documented. They may present with swelling, pain during function, limited mouth opening, crepitus, occlusal changes, and/or sensory-motor changes. Facial asymmetry with a midline shift may occur as the lesion expands. Diagnostic imaging, typically using CT/CBCT and/or MRI, and biopsy are essential when a neoplasm is suspected.
Histopathological criteria for osteochondroma
- Periosteum appears as pink fibrous capsule. Cartilage resembles disorganized growth plate with ossification toward base. Medullary cavity merges with that of underlying bone (pathologyoutlines.com/).
Expanded DC/TMD criteria For TMJ osseous ankylosis (Peck et al., 2014), see Case 2.8