Targeted 3T MRI is highly accurate in defining the presence and extent of large nerve PNS in head and neck cancers. However, there is still a tendency to undercall the zonal extent due to microscopic, radiologically occult involvement. Superficial large nerve involvement also remains a difficult area of detection for radiologists and should be included as a 'check area' for review. Further research is required to define the role radiation-induced neuritis plays in the presence of false-positive PNS on MRI.

We present a review of the imaging surveillance following treatment for large nerve perineural spread in the skull base. The expected appearance and possible complications following surgery and radiotherapy are discussed. Imaging examples of the possible sites of disease recurrence are also presented.

We present a review of the imaging findings of large nerve perineural spread within the skull base. The MRI techniques and reasons for performing different sequences are discussed. A series of imaging examples illustrates the appearance of perineural tumor spread with an emphasis on the zonal staging system.

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Lymphoepithelial carcinoma (LEC) is a rare malignancy of the salivary gland arising from the parotid in 80% of cases. LEC is indistinguishable histologically from more common non-keratinising undifferentiated nasopharyngeal carcinoma (NPC). Up to 40% of patients with primary LEC present with a cervical metastasis and histological assessment of the primary lesion or nodal metastasis may be reported as NPC. The absence of a nasopharyngeal lesion on imaging and endoscopic assessment together with a parotid mass strengthens the case for a LEC. A retrospective review of three cases of primary parotid LEC presenting to a tertiary head and neck clinic was performed. Clinical information, imaging and histopathology findings are presented in the form of a pictorial review. Two female and one male patient with an average age of 42 years presented with a neck lump. Initial pathology results were poorly differentiated carcinoma (2/3) and possible NPC (1/3). MR neck revealed unilateral parotid masses with ipsilateral cervical lymphadenopathy and assessment of the nasopharynx was negative (3/3). Resection occurred in all patients and consensus was metastatic LEC with parotid primary in all cases (3/3). 2 patients are disease free, and 1 patient is deceased (as a result of disease) at the time of this report. Lymphoepithelial carcinoma is identical histologically to NPC, this pictorial review highlights the need for clinical and radiological correlation to establish the diagnosis.