Osteochondromatosis of the temporomandibular joint.

Abstract

Osteochondromatosis denotes the presence of cartilaginous and osteocartilaginous bodies within or near a joint arising from the synovial membrane. The knee joint is the most frequent site, with the elbow next in order. Rarely, other joints may be involved. The purpose of this paper is to report a single case involving the temporomandibular joint proper. To the best of our knowledge no similar cases have been described, although osteochondromas of the coronoid process of the mandible and of the zygomatic arch have been reported (1–3). Case Report A 59-year-old white female was admitted to the Presbyterian Hospital of Pittsburgh on Sept. 21, 1956, complaining of pain in the right temporomandibular joint of one year duration. The pain, sharp and stabbing in nature, was present on chewing and yawning and was referred to the right ear and mastoid region. Extraction of a third molar tooth failed to afford relief, and the patient was readmitted on Dec. 13 with the same complaint as on her earlier admission. At this time, examination revealed a hard mass under the right temporal muscle. Pressure over this area produced discomfort but no real tenderness. Radiographs (Figs. 1 and 2) of the temporomandibular joints were obtained, and the report was as follows: “The condylar and coronoid processes of the right mandible appear intact. A calcified body is present in the joint space, and a second semicircular body is present in the space between the coronoid and con-dylar processes of the mandible. Scattered intervening calcifications are present. The left temporomandibular joint appears normal.” Surgical exploration was performed Dec. 29. A freely movable, loose body measuring 1.0 × 1.0 × 1.5 cm. was removed from the right temporomandibular joint. Subsequent histopathologic examination showed this to be osteocartilaginous in nature. A follow-up radiograph (Fig. 3) and laminagraph (Fig. 4) demonstrated persistence of the previously noted semicircular body between the coronoid and condylar processes, possibly slightly increased in its calcified portion and containing a radiolucent cartilaginous center; another smaller densely sclerotic body was interposed between the condyloid fossa and condylar process. The latter may represent either a recurrence of the previously excised lesion from its synovial origin, a small third body not discernible preoperatively, or the remnant of the base of the resected lesion. Discussion The etiology of osteochondromatosis is unknown. Many consider that the osteocartilaginous bodies arise from embryonic rests in the synovial membrane. The most widely held hypothesis within recent years regards the condition as a benign neoplasm (4), but Jaffe suggests the theory of metaplastic development from the “sublining connective tissue of the synovial membrane” (5).