PMC4818305_01
(a,b) The right-side mandibular condyle was displaced anteriorly by a mass lesion and severe bone resorption from the glenoid fossa to middle cranial fossa was observed on simple X-ray (a) and CT (b). (c-e) A large mass lesion near the cranial dura mater was confirmed on MRI, but invasion into the brain was not observed (c,e) PdWI, (d) T2WI).
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The right mandibular condyle was displaced anteriorly and a severe bone defect from the glenoid fossa to middle cranial fossa was observed on simple X-ray and CT images (Fig. 1a,b). The signal intensity of the tumor mass was intermediate in PDWI and mixed heterogeneous high signal intensity and spotted low signal intensity regions were present in T2WI (Fig. 1c-e).
(a,b) Intraoperative photographs. A bone defect of about 1 cm diameter in the gleinoid fossa was observed after extirpation. (c) Intraoperative findings. The illustrations are taken from the operative notes for the case. The annotations were translated into English by the author. (d-f) The specimen consisted of nodules of cartilage and was surrounded by a capsule of the synovial connective tissues. Mineralization of the cartilage was observed.
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TMJ was performed through a temporopreauricular incision under general anesthesia in September 2005 (Fig. 2a-c). The mass lesion was extirpated completely with the surrounding capsule. Penetration of the middle cranial fossa was observed, but the cranial dura mater was intact (Fig. 2b,c). The mass lesion seemed to be composed of cartilaginous tissues (Fig. 2d). Pathological findings showed that the specimen consisted of nodules of cartilage and was surrounded by a capsule of synovial connective tissues, with mineralization of the cartilage (Fig. 2e,f).
(a-d) CT (a,b) and MRI (c,d) at 6 months after surgery. Arrows indicate new bone formation of the glenoid fossa.
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Malocclusion, limitation of mouth opening and TMJ pain improved after surgery and new bone formation of the glenoid fossa was observed on CT and MRI at 6 months postoperatively (Fig. 3a-d).
(a,b) CT at 7 years after surgery (a,b). The bone defect of the glenoid fossa had decreased compared with CT at 6 months after surgery ((a,c) sagittal plane, (b,d) frontal plane). (c-e) MRI at 7 years after surgery ((a) sagittal plane on PdWI, (b) sagittal plane on T2WI, (c) frontal plane on T2WI). A mixed high and low signal intensity area was observed behind the condyle on T2WI (arrows).
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Further irregular bone resorption was not observed on CT images at 7 years postoperatively and the bone defect of the glenoid fossa was decreased compared with CT images at 6 months postoperatively (Fig. 4a,b). MRI findings at 7 years postoperatively showed a mixed high and low signal intensity area behind the condyle on T2WI (Fig. 4c-e).
Immnohistochemical detection of PCNA in chondrocytes in the resected specimen. Arrows indicate typical PCNA-positive cells. Original magnifications, x200.
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PCNA-positive chondrocyte-like cells were found (Fig. 5a-c).