Abstract
Ganglion cysts are benign soft tissue tumours occurring in or near joints such as the wrist, foot or knee. They are rarely encountered in the region of the temporomandibular joint (TMJ). The authors report a ganglion cyst of the TMJ in a 56-year-old woman. The patient experienced pain and presented with a prominence in the right TMJ region, anterior to the tragus. She had some divergence in skin sensation in the right mental region of mandible. Magnetic-resonance imaging showed a rounded hypodense mass of soft tissue lateral to the right TMJ region. The surgical excision of the tumour was performed through a preauricular approach extending to the temporal region. During the 6-month postoperative follow-up there was no sign of recurrence. Surgical excision should be the treatment of choice for ganglion cysts in the region of TMJ.
Ganglion cysts are benign soft tissue tumours occurring in or near to joints such as the wrist, foot or knee but they are rarely encountered in the region of the temporomandibular joint (TMJ). They seem to originate from myxoid degeneration of the collagenous tissue in the capsule of the joint and do not connect with the joint cavity. The clinical diagnosis of the condition is difficult, with accurate diagnosis being made through intraoperative observation and postoperative microscopic examination.
This report presents a case of ganglion cyst found lateral to the TMJ. It was treated successfully by surgical removal of the tumour.
Case report
A 56-year-old Finnish woman was referred to the Department of Oral and Maxillofacial Diseases, Kuopio University Hospital, Kuopio, with a 5-month history of a prominence in the preauricular region of the right TMJ where she had also experienced pain. The prominence had not grown in size during this period. She had noticed some divergence in skin sensation in the region of the right maxillary and mandibular branches of the trigeminal nerve but she was not aware of any traumatic injury to the TMJ region.
Her medical history, revealed she was taking no regular medication and she was not a smoker. During the past year, due to arthritis, she had undergone surgery of the metatarsal joint of the right big toe, which had subsequently been asymptomatic.
Her physical examination revealed a firm, circumscribed prominence, measuring 10 mm in diameter, anterior to the tragus, on the right preauricular region. The tumour was not attached to the skin. The patient had normal mouth opening with no deviation. The mandibular ranges of motion were normal in all directions, but there was a slight painful sensation during protrusion. There was no sound in the TMJ on auscultation during mandibular motion. The tumour seemed to disappear during mouth opening. The patient experienced slight pain on the right TMJ on palpation while biting forcefully. The external auditory canals and tympanic membranes were intact and clear. The skin sensation was slightly blunted in the region of right maxillary and mandibular branches of the trigeminal nerve. There was no facial nerve paresis. No abnormality was observed in the regional lymph nodes. The rest of the head and neck examination was unremarkable.
A routine radiograph of the TMJ showed no abnormality. T1- and T2-weighted magnetic resonance imaging (MRI) was performed to clarify the pathological features and to locate the tumour more precisely. The tumour was located lateral to the right TMJ and in close contact with the right parotid gland. The density of the tumour showed fluid consistency. No intracranial tumour expansion was detected. Fine needle aspiration of the lesion was performed under ultrasound guidance. The sample revealed a bright gel-like substance containing large numbers of macrophages. No epithelium was observed. Based on the fine needle aspiration, no definitive diagnosis could be made. The coronal and sagittal T2-weighted MRIs are shown in Figs. 1 and 2 , respectively.
Computed tomography (CT) of the base of the skull was performed, because of the slightly blunted skin sensation in the region of the right maxillary and mandibular branches of trigeminal nerve, but it revealed no abnormalities.
Surgical excision was carried out under general anaesthesia. A standard preauricular approach extending to the temporal region was performed to gain access to the right TMJ. The incision was made through the skin, subcutaneous tissue, temporoparietal fascia, and superficial layer of the temporal fascia. The incision through the superficial fascia was made at the level of the zygomatic arch. The preparation was continued on the lateral surface of the capsule of the TMJ. A 15 mm × 12 mm × 8 mm-sized tumour was exposed bluntly from the surrounding tissues. The tumour was connected from a single point to the lateral surface of the capsule of the TMJ and had no connection to the joint cavity or the parotid gland. The tumour was sharply excised in its entirety ( Figs. 3 and 4 ).
