Giant Cell Granuloma of the temporal bone
23 April 2019 (online)
Giant cell granulomas (GCG) are rare, non-neoplastic, osteolytic lesions predominantly found in the gnathic bones. Since the first report by Hirschl and Katz in 1974 several cases of GCG with manifestation in different locations like the short bones of hands and feet, long bones of the extremities and vertebrae were detected. Nevertheless, the occurrence of GCG in the temporal bone is a rarity and only a few cases are reported in literature.
This article presents the case of a 45-year-old patient with GCG located in the right temporal bone.
The patient was admitted to the hospital due to right-sided hearing impairment. In the clinical examination a bulging of the anterior wall of the right external auditory canal was demonstrated which correlated with an osteolytic lesion in the anterior temporal bone shown on subsequently performed CT and MRT scans. The lesion reached the temporomandibular joint, eroded the temporal calvaria and protruded into the middle fossa with a total diameter of 3 cm. After histopathologic examination of tissue extracted via an endaural approach, identifying the lesion as GCG, we performed a complete resection of the lesion via an infratemporal fossa approach type B (as described by Fisch). Upon removal, the lesion was found to have attachments to the dura of the middle fossa with no intra-axial extension.
Preoperative diagnosis of GCG is challenging as differential diagnosis like giant cell tumor, brown tumor of hyperparathyroidism and aneurysmal bone cyst can present themself in a similar fashion. With ruling out the potential differential diagnosis no further treatment is indicated after complete radical resection but follow up examination should be performed as a recurrence rate of 10% is described in literature.