2004, Number 2
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ABSTRACTPerineural dissemination (PD) is a very important finding in the evaluation of malignant head and neck neoplasms. It usually implies tumoral non-resectability and must be differentiated from other oncologic clinical situations with neurological manifestations. The clinical alterations can be sensitive or motor and the most frequently affected nerves are the facial and trigeminal nerves. Changes in imaging studies, especially in Magnetic Resonance Imaging are more sensitive than the clinical findings. For these reasons the role of the Radiologist is key in the diagnosis of this disease and implies knowing the related neuroanatomy.
High risk sites for PD are the pterigomaxillary fossae, parotid gland, masticator space, orbital fissures, skull base foramina, cavernous sinus and Meckel´s cave. Some of these areas have a predominantly adipose content, while Meckel´s cave has a similar appearance to CSF, which is shown in the normal imaging studies.
The signs in Magnetic Resonance Imaging are alterations of the normal signal characteristics of the region, as well as increase in nerve size and enhancement. Computed Tomography is less sensitive in the detection of these changes; nonetheless, it shows alterations in the cortical area of the foramina.
The objectives of this article are: review the characteristics of perineural dissemination of head and neck neoplasms, with emphasis in the decisive role of the Radiologist. Analyze the appearance with Magnetic Resonance Imaging and Computed Tomography, and to present some representative cases of each type of lesion.
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