Anatomy of the temporal bone

High resolution computed tomography has proved to be invaluable in the evaluation of the temporal bone, and demonstrates its bony anatomy in exquisite detail. Furthermore, the role of magnetic resonance imaging, especially with improving high resolution techniques, has continued to expand in the past decade. A thorough understanding of normal temporal bone anatomy is a requisite for accurate radiologic evaluation. The ensuing discussion is an attempt to summarize the normal temporal bone anatomy with emphasis on clinically relevant structures, temporal bone pneumatization, and common anatomic variants.     

Meningiomas of the temporal bone

Meningiomas should be considered in the differential diagnosis of otologic tumors arising from the middle ear and mastoid. It is generally recognized that meningiomas may invade the temporal bone via direct extension from the intracranial space (secondary). It is not generally recognized that meningiomas can develop initially in the middle ear cleft (primary). Representative cases of primary and secondary meningiomas of the temporal bone are described and clinical aspects of diagnosis surgical management are discussed. In order to assess the pathogenesis of meningiomas of the temporal bone, histological studies were done on 200 temporal bone specimens. In certain specimens, ectopic arachnoid granulations, from which primary meningiomas may originate, were identified and described, according to location. One specimen was most unusual in that it contained ectopic glial as well as arachnoidal tissue.     

Quantitative bone scintigraphy in the management of monostotic Paget's disease of bone

OBJECTIVE: To assess the use of quantitative bone scanning (QBS) in the monitoring of patients with intravenous pamidronate-treated symptomatic monostotic Paget's disease of bone in whom biochemical markers of bone turnover are relatively normal. METHODS: QBS was performed in 9 patients and the results were expressed as a ratio, obtained by comparing isotope uptake at an affected and a control (unaffected) site. RESULTS: Serum alkaline phosphatase levels were normal in 7 of the 9 patients and changed minimally with treatment. The median QBS ratio was 2.72 (range 1.69-24.6) at baseline and 1.49 (range 0.63-4.18) posttreatment (P = 0.008). The median symptom score decreased with treatment, but QBS ratios provided the only objective measure of disease activity by which response to pamidronate therapy could be judged. CONCLUSION: QBS may be a useful technique for evaluating the effects of treatment in patients with Paget's disease of bone.     

Sclerosing lesion of the sphenoid bone. Fibrous dysplasia of the sphenoid bone of the sclerosing type]

A 3-year-old Quarter Horse gelding was treated for left guttural pouch mycosis by ligation and balloon catheterization of the left internal carotid artery. Catheter advancement was shorter (10 cm) than the normally reported distance (13-15 cm), but was observed endoscopically during placement as it coursed within the internal carotid artery through the guttural pouch. The horse developed a persistently abnormal respiratory pattern after catheter placement, failed to gain consciousness, developed pulmonary edema, and died 5.5 hours postoperatively. Postmortem examination revealed an aberrant left internal carotid arterial course with location of the embolectomy catheter at the junction of the basilar and caudal cerebellar arteries. Brainstem neuronal necrosis and alveolar and interstitial pulmonary edema were identified on histological examination. Angiography may be used to identify aberrant branching patterns. Failure to identify and occlude aberrant branches may result in fatal epistaxis and Brainstem lesions.     

Glomus tumor of the temporal bone

A case story describing the typical symptoms and course of a glomus tumour of the temporal bone is presented. The most frequent symptoms are pulsatile tinnitus, unilateral hearing loss, aural fullness and paresis of the vagal nerve or other lower cranial nerves. The tumour is frequently visible by otoscopy. Despite being histologically benign, the tumour is infiltrative and may affect the surrounding cranial nerves or spread into the cranial cavity. The early signs and findings are vague. Since the sequelae are fewer when the tumour is treated while it is small, an increased awareness will be of benefit to the patients.     

Aneurysmal bone cyst of the fibula

Aneurysmal bone cysts are benign, expansile lesions that are not at all uncommon in the lower extremity. These lesions are difficult to recognize clinically. This paper is a thorough review of the current literature regarding aneurysmal bone cysts. After this review, one should be able to diagnose and appropriately treat aneurysmal bone cysts. Also provided is a case report with classic histologic, clinical, and radiographic findings that was treated by en bloc resection.     

Desmoplastic fibroma of the temporal bone

BACKGROUND: Desmoplastic fibroma is a benign, locally aggressive, intraosseous neoplasm with a propensity for local recurrence. Desmoplastic fibroma most commonly originates within the mandible (70% of cases), and long bones with rare lesions reported in the maxillary, frontal, and parietal bones. We report two patients with desmoplastic fibroma arising within the temporal bone. STUDY DESIGN: Case report and literature review. PATIENTS: Two patients with desmoplastic fibroma with intracranial and extra cranial growth patterns are presented. Both were young females with aural fullness and decreased hearing. INTERVENTIONS: Diagnostic and therapeutic. RESULTS: Both tumors were surgically extirpated and the patients have remained disease free for 18-48 months. Neither tumor expressed estrogen or progesterone receptors. CONCLUSION: Desmoplastic fibroma is a highly invasive local destructive lesion which is best treated by nondestructive surgical intervention. Immunohistochemical analysis may demonstrate hormonal receptors, in which case Tamoxifen may reduce recurrence.     

Osteoid osteoma of the petrous bone

We present a case of osteoid osteoma of the petrous bone presenting with progressive sensorineural hearing loss. CT showed a dense homogeneous mass at the promontory surrounded by a thin bony border. On MRI this lesion gave intermediate signal intensity on T1- and T2-weighted spin-echo images and enhanced intensely with gadolinium. Surgical removal and pathological study proved the diagnosis.     

Paradoxical bilateral asymmetry in bone size and bone mass in the hand

Among 227 chronic renal disease patients, micrometer caliper radiogrammetric measurements of the second metacarpal at midshaft showed the right metacarpal to be larger (with greater bone area) and with a greater cortical area than the left second metacarpal, both in 208 right-handed individuals and in 19 left-handed individuals. This direction of asymmetry was individually characteristic of the majority of individuals, whether right-handed, left-handed or ambidextrous.