The use of MRI for the evaluation of lesions in the internal auditory canal presents a potential pitfall in the diagnosis of bony lesions of the IAC, because bone is poorly visualized with this method of imaging. The presence of marrow in an osteoma might aid in its detection, since fat in the marrow has a bright signal intensity of T1-weighted imaging. Computed tomography remains the imaging modality of choice for bony lesions of the temporal bone. We demonstrate a case of IAC osteoma in which surgical removal resulted in improvement of symptoms. The gross and microscopic appearance of the IAC osteoma in this case is similar to the characteristic findings of osteomas of the EAC. This suggests that the criteria applied to osteomas and exostoses of the EAC may also be used to differentiate bony lesions of the IAC.
Fifty patients with medically refractory partial seizure disorders have undergone subdural electrode placement for seizure focus localization. Standard scalp telemetry recordings of ictal events had failed to demonstrate accurately the site of seizure onset, and these patients were considered candidates for telemetry with intracerebral depth electrodes. Excellent recordings of interictal and ictal events were obtained, and localization of the epileptogenic focus was derived from recordings made during spontaneously occurring seizures. Electrocorticograms were monitored for up to 21 days. The recordings enabled a surgical decision to be made in 43 of 50 cases (86%). Thirty patients have subsequently undergone cortical excision of their foci with good results. Subdural electrode recordings are a significant addition to the armamentarium of the neurosurgeon attempting to localize surgical seizure foci, offering a low morbidity procedure as an alternative to depth electrode implantation.
The acute onset of cyanosis in any patient is an alarming development, usually suggesting hypoxia. In the patient with head and neck cancer, hypoxia resulting from airway obstruction, pneumothorax, pulmonary thromboembolism, or an acute exacerbation of chronic obstructive pulmonary disease is the chief consideration in the differential diagnosis. Cyanosis rarely occurs in the presence of adequate oxygenation. However, this unusual combination is seen with methemoglobinemia. We present a case of methemoglobinemia that occurred after the use of topical anesthetics during the workup of a head and neck tumor. CASE REPORTD.O. is a 61-year-old man with a T 2NoM o squamous cell carcinoma of the floor of mouth who was undergoing evaluation for a suspected simultaneous primary carcinoma of the lung. Immediately after an uncomplicated fiberoptic bronchoscopy and transbronchial needle biopsy while he was under local anesthesia, the patient became cyanotic. The patient's physicians were summoned and noticed a nearly black appearance of the lips, ears, face, tongue, and digits (Fig. 1). D.O. was in no acute distress, had stable vital signs, and reported slight weakness and a headache (only the second of his lifetime).Auscultation revealed equal breath sounds and a portable chest radiograph disclosed no evidence of pneumothorax. Oxygen was administered at a rate of 6 liters per minute per nasal cannula. Arterial blood gases (ABGs) Weredrawn from the right radial artery and the blood was noted to be a dark, blue-black color. Pulse oximetry revealed oxygen saturations in the low to mid-80s. The ABG results were: pH = 7.37; PaC02 = 47 mmHg; Pa02 = 125 mmHg; percent oxygen saturation = 98%.The patient's cyanosis did not respond after several min-
H|V|ucormycosis is a fungal infection caused by a member of the family Mucoraceae of the subclass Zygomycetes of the class Phycomycetes. Within this subclass are the genera Rhizopus, Mucor, and Absidia. Morphologically, they are nonseptate, broad hyphae (5 to 50 fxm), with branches at right angles. They may be seen histologically with hematoxylin and eosin staining, Grocott-Gomori methenaminesilver nitrate staining, and occasionally periodic acid-Schiff stainingJ -3 They invade tissue with a particular affinity for blood vessels, leading to thrombosis and tissue ischemia. 4 These fungi are ubiquitous in bread and fruit molds and may be found in soil, manure, plants, vegetable matter, and air] '5'6 There is some evidence that they are present in the gastrointestinal and respiratory tracts of healthy individuals. 1' 6 Rhizopus is responsible for 60% of all cases of mucormycosis and 90% of rhinocerebral mucormycosis. In the majority of cases of rhinocerebral mucormycosis, the organism gains access to the patient through the nose] This fungi may, however, enter through any disruption of mucosa or skin/ It is reported that there are as many as seven clinical syndromes of mucormycosis. 8 The five major forms include (1) rhinocerebral, the most common and the most fatal; (2) pulmonary; (3) gastrointestinal; (4) disseminated; and (5) cutaneous. 5 A rare form, nasopharyngeal mucormycotic osteitis, has also been reported, 9 as have a few cases of isolated central nervous system involvement. 1°-12The first case of mucormycosis was reported by Paltauf in 1885, but it was not until 1955 that Harris
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