Successful function-preserving therapy for chondroblastoma of the temporal bone involving the temporomandibular joint

Abstract

We present a case involving a late diagnosis of chondroblastoma of the temporal skull base involving the temporomandibular joint (TMJ). Following an initial misdiagnosis and unsuccessful treatment over a period of 5 years, the patient was referred to our department for further evaluation and possible surgical intervention for occlusal abnormalities, trismus, clicking of the TMJ, and hearing impairment. Based on preoperative immunochemical studies showing positive reaction of multinucleated giant cells for S-100 protein, the final diagnosis was chondroblastoma. The surgical approach - postauricular incision and total parotidectomy, with complete removal of the temporal bone, including the TMJ via the extended middle fossa - was successful in preserving facial nerves and diminishing clinical manifestations. This study highlights a misdiagnosed case in an effort to underline the importance of medical examinations and accurate differential diagnosis in cases involving any tumor mass in the temporal bone.

Keywords: Chondroblastoma; Parotidectomy; Temporal bone; Temporomandibular joint; Trismus.

Fig. 1

Preoperative CT scans showing invasion of the tumor mass into the right temporal lobe. The arrows point out the tumor mass in the right intra-temporal lobe, invading the middle cranial fossa. a Sites indicating boney destruction in the middle cranial base. b Inferior sites responsible for the trismus.

Fig. 2

Preoperative axial T1-/T2-weighted MR image showing invasion of the tumor mass into the right temporal lobe. The arrows point out the tumor mass in the right intra-temporal lobe, involving the right middle cranial and infratemporal fossae, and the presence of a poorly defined mass with low and relatively high signal on T1- (left) and T2- (right) weighted sequences, respectively.

Fig. 3

Histopathologic cut confirming the diagnosis of chondroblastoma (HE, a ×100, b ×400). Microscopic examination revealed poorly circumscribed tumor with scattered multinucleated giant cells and multiple aneurism-like bone cysts with the presence of hemorrhage, representing secondary aneurismal bone cyst formation. Immunochemical staining indicates reactivity of the neoplastic cells for S-100 protein (c).

Fig. 4

Display of the technique for postauricular incision and total parotidectomy leaving facial nerves intact. Arrow head shows resected ramus mandible as well as resected dura. Facial nerves are preserved (a). Radical mastoidectomy and temporal craniotomy, preventing infection and dysfunction is shown (b). The detailed operative techniques are described in the text. 1 = Facial nerve; 2 = resected ramus mandible; 3 = SCM muscle reconstructed; 4 = fat covering the tympanic cavity; 5 = temporal bone; 6 = pericranial flap.

Fig. 5

Reconstruction of facial tissues using a modified surgical procedure. Facial palsy and surgical scar are not prominent after reconstructive surgery (upper two photos). Both upper and lower malocclusions of teeth are aligned (lower left photo) and chondroblastoma-induced trismus significantly improved postoperatively (lower right photo).