|Year : 2009 | Volume
| Issue : 3 | Page : 130-133
Osteochondroma of the condyle
Karthikeya Patil, VG Mahima, Sujith Shetty, S Sudhakar
Department of Oral Medicine and Radiology, J.S.S. Dental College and Hospital, Mysore - 570 015, Karnataka, India
|Date of Web Publication||7-Jan-2010|
Department of Oral Medicine and Radiology, J.S.S. Dental College and Hospital, S.S. Nagar, Mysore - 570 015
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Osteochondroma, also known as osteocartilaginous exostosis, is a benign cartilage capped outgrowth attached to the underlying skeleton by a short stalk. Osteochondroma is frequently seen in the axial skeleton but rarely occurs in the craniofacial skeleton. We report a case of osteochondroma arising from the right mandibular condyle.
Keywords: Cartilaginous cap, condyle, condylectomy, endochondral ossification, osteochondroma
|How to cite this article:|
Patil K, Mahima V G, Shetty S, Sudhakar S. Osteochondroma of the condyle. J Indian Acad Oral Med Radiol 2009;21:130-3
| Introduction|| |
Osteochondroma is a benign neoplasm affecting the bones that develops by endochondral ossification. Despite its predilection for the long bones, it may occur in any bone that develops by intramembranous ossification. Osteochondroma of the condyle is a rare entity and accounts for 1-2% of benign tumors of the jaw. It poses a diagnostic dilemma as the signs and symptoms resemble TMJ dysfunction.
| Case Report|| |
A 39-year-old male patient reported to the department of oral medicine and radiology with a complaint of pain in front of his right ear since six months. The pain was mild, insidious in onset, aggravated on chewing food, and during wide mouth opening. The patient claimed that the intensity of pain had increased over the past 15 days and that it subsided only after taking painkillers and muscle relaxants. There was no history of swelling, paresthesia, neurological deficit or loss of hearing. The past medical and surgical histories were unremarkable. The family history was not significant. The patient did not report any parafunctional or deleterious habits.
General physical examination revealed a moderately built and nourished male patient with vital signs within satisfactory limits. The regional lymph nodes were not palpable.
Extra-oral examination revealed bilateral symmetry of the face with no mandibular deviation [Figure 1]. The mandibular protrusive and lateral excursive movements were accompanied by mild pain. The maximal mouth opening measured from the tip of the incisal edge of the maxillary central incisor to the mandibular central incisor was 43 mm. On palpation mild tenderness over the right TMJ and right masseter was noted. On auscultation no abnormality was detected.
Intra-oral examination showed posterior open bite of about 2-3 mm on the right side whereas maximal intercuspation of the molars was present on the left side [Figure 2]. Mild tenderness over the right lateral and medial pterygoid was elicited on palpation.
Based on the history and clinical examination a provisional diagnosis of condylar/coronoid hyperplasia was made and differential diagnoses of osteoma, chondroma, osteochondroma, fibro myxoma and giant cell tumor were considered.
The patient was subjected to radiological investigations. The panoramic view showed a well-defined expansile radiopaque mass ranging from 1 to 1.5 cm in size arising from the neck of the right condyle from its medial aspect. The radiopaque mass had well-defined borders and its shape resembled that of a swan's beak. The internal densities of the mass were uniformly radiopaque and were similar to the density of the condyle [Figure 3].
The TMJ open and closed views showed disarticulation on the right condylar head out of the glenoid fossa whereas the left condylar head had normal articulation [Figure 4].
Computed tomography of the condyle in coronal, axial and sagittal sections showed a large pedunculated osseous protuberance attached by a stalk arising from the anterior aspect of the right mandibular condyle [Figure 5].
The radiological findings were suggestive of a slow growing bony tumor involving the right condyle, probably with cartilaginous involvement.
A panel of experts comprising oral diagnosticians and oral surgeons considered the age of the patient, symptomatic nature of the lesion and the effect of the mass on occlusion and decided to perform high condylectomy with excision of the growth.
Under general anesthesia using standard pre-auricular incision the TMJ was exposed surgically. The growth was identified intra-operatively and the mass was excised at the condylar head with stripping of its muscular attachments. The meniscus was preserved. Hemostasis was obtained and closure was done in layers. Eyelet wiring was done to immobilize the mandible post-operatively and guided training elastics were placed for two weeks. The postoperative period was uneventful and the maximal intercuspation was obtained after two weeks.
Histopathological examination of the excised mass showed dense spicules of lamellar bone interspersed with fibrous fatty marrow and capped by cartilage of varying thickness. Focal areas of active chondrocytes with endochondral ossification at the osteocartilaginous junction were noted [Figure 6].
Based on the history, clinical, radiographic and histopathological correlation a final diagnosis of osteochondroma of the right condyle was rendered.
| Discussion|| |
Osteochondroma is characterized by hyaline cartilage at the periphery of the tumor, which ossifies upon cessation of growth.  Osteochondroma is frequently seen in the axial skeleton. The most common locations of the tumor are the distal metaphysis of the femur and the proximal metaphysis of the tibia. ,
An osteochondroma of the facial skeleton is a rare occurrence. When present the tumor is most commonly associated with the coronoid process.  Other sites such as posterior maxilla, symphysis, gonion, zygomatic arch, ramus and maxillary sinus have also been reported. ,,,, Osteochondroma of the mandibular condyle as seen in our case is an extremely rare entity. , The osteochondroma of the condyle appears as a cartilage-capped exostosis arising from the condyle. Grossly, the lesion is usually lobulated or irregular in contour and causes deformation of the normal condylar morphology.  Osteochondroma can alter the morphology of the condyle to any shape, however the swan-like appearance of the condyle as seen in our case is meager in the literature.
Condylar osteochondromas are usually unilateral and situated on the anteromedial surface of the condylar head,  as seen in our case. For unknown reasons the left condyle is more likely to be affected, , but in the present case the right side was involved. The tumor is most frequently diagnosed in late adolescence and early adulthood. , Males, as in the present case, are affected three times more than females. The vast majority of the patients develop solitary lesions and some multiple osteochondromas apparently have a hereditary basis.
The cause of the lesion is not clear. Trauma and inflammation may play a role in some instances as either an initiating factor or a predisposing factor. Cases of birth trauma from forceps delivery or disturbances due to infection of the joint are not uncommon. However, our case did not have any history of trauma.
Three etiological theories have been presented in the literature. Langenskiold theorized that the lesions result from a proliferation of the cells of the undifferentiated cell layer of the epiphysis and subsequent displacement of the cells to the metaphysis. This theory does not seem to explain the tumor's presence in the condyle. Geshickter and Copeland theorized that normal focal accumulations of cells with cartilaginous potential exist at all points of tendonous insertion. Continued stress and strains at these points might cause hyperplastic changes in these collections which could result in osteochondroma. The most appealing theory for lesions in extracondylar locations, in which tendon insertions are not present, was proposed by Lichenstein. He suggested that as the periosteum has the potential to develop osteoblasts as well as chondroblasts, the lesion could result from a spontaneous or induced metaplasia of the periosteum, which might form cartilage that subsequently undergoes endochondral ossification. ,
The tumors are usually slow growing and symptoms develop over a long time. The most common presentation of the condylar osteochondroma consists of changing occlusion, the development of facial asymmetry and a posterior apertognathia on the affected side. Limitations of condylar motions with clicking sounds are not common with condylar tumors but are often with tumors of the coronoid process. ,,
Radiographically the tumors appear as an irregular shaped enlargement of the condyle exhibiting varying densities.  Grossly, they are lobulated resulting in deformations of the normal condylar morphology. Advance imaging modalities are helpful in determining the extent of the lesion. More recently, bone scan using technetium 99 methyl diphosphonate performed with single photon emission tomography (SPECT) has been used, which enables more accurate determination of the extent of the tumor. 
Histological appearance of the lesion consists of dense spicules of lamellar bone interspersed with fibrous fatty marrow and capped by cartilage of varying thickness. Endochondral ossifications are often seen at the osteocartilaginous junction.
The radiographic differential diagnosis of solid lesions of the condyle includes condylar hyperplasia, condylar hypertrophy, osteoma, chondroma, giant cell tumor, myxoma, ameloblastoma, fibro-osteoma, fibrous dysplasia, fibrosarcoma and metastatic disease. ,
Treatment consists of surgical resection either by intra-oral or extra-oral approach which includes condylectomy, condylar shaving or reshaping depending upon the size of the lesion ,, and subsequent reconstruction with free autogenous bone graft such as ileac crest costochondral graft or with a local osseous pedical graft. Another alternative is titanium mesh which is biocompatible and more functional in nature. ,
Osteochondroma rarely undergoes malignant transformation; approximately 10% of the patients with multiple osteochondromas can develop into chondrosarcoma. , However this reported risk is probably overstated as well; studies of family pedigree with this autosomal dominant inherited disease suggest that the true incidence is closer to 1%.  A rare case of osteochondroma of the nasal septum developing into a chondrosarcoma has also been reported. ,
| Conclusion|| |
Osteochondroma of the mandibular condyle presenting as a symptomatic mass is a rarity. This necessitates an improved understanding of the clinical spectrum of the entity. Timely diagnosis, appropriate conservative treatment in initial stages and surgical correction in advanced stages are mandatory for complete resolution of the symptoms, to prevent possible complications and to improve the patient's lifestyle.
| Acknowledgments|| |
The authors thank Dr. Lakshman, M.D., General Pathologist, Kannan Diagnostics, Mysore for the histopathological report.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]