A number of histopathologic parameters in squamous cell carcinoma of the oral cavity and oropharynx have been identified as having a statistically significant correlation with regional lymph-node metastasis. These parameters have been inconsistent and not readily reproducible. In an attempt to confirm these parameters, a retrospective analysis of 22 patients with T1 to T4 squamous cell carcinoma of the oral cavity and oropharynx was performed. Initially, these patients were managed with either wide local excision or surgical excision of the primary tumor combined with radical neck dissection. There was a minimum of 3 years of follow-up. Chi-square contingency tables and Fisher's Exact Test were used to correlate histopathologic parameters with lymph-node metastasis. Statistically significant correlations were found for tumor thickness and inflammatory infiltrate.

For adequately experienced cytopathologists, ThinPrep is acceptable for FNA of salivary masses, neck cysts, metastatic lymph nodes, and thyroid lesions. Conventional smear technique should be used for FNA of nonmetastatic lymphoid lesions. Use of ThinPrep can complement use of the conventional (smear) cytopreparatory technique when aspirate is nondiagnostic or bloody, when the patient has a blood-borne infectious disease, when the clinician is inexperienced, or when aspirate has entered the syringe.

A method for directly simulating coherent backscattering of polarized light by a turbid medium has been developed based on the Electric field Monte Carlo (EMC) method. Electric fields of light traveling in a pair of time-reversed paths are added coherently to simulate their interference. An efficient approach for computing the electric field of light traveling along a time-reversed path is derived and implemented based on the time-reversal symmetry of electromagnetic waves. Coherent backscattering of linearly and circularly polarized light by a turbid medium containing Mie scatterers is then investigated using this method.

✓ An unusual case of a sacral, extradural choroid plexus papilloma involving the S1–3 level is described. This 50-year-old woman presented with a 4-month history of pain involving her right buttock, perineum, and leg. Contrast-enhanced magnetic resonance (MR) imaging of the spine revealed a well-defined, mildly enhancing sacral canal mass at the S1–3 level; its appearance was consistent with that of a benign tumor. Intraoperatively, the lesion was found to be extradural in location and was entwined among nerve roots in the sacral canal. Microscopic examination of the gross totally resected tumor revealed typical features of a choroid plexus papilloma. Despite performing a thorough neuroimaging workup (craniospinal contrast-enhanced MR imaging) for an intracranial or spinal primary mass, none was found. The choroid plexus appeared entirely normal; however, both a cavum septum pellucidum and a cavum vergae were noted. Extraneural choroid plexus papilloma, specifically intrasacral, extradural choroid plexus papilloma has not been previously reported. The present example is thought to have arisen either from ectopic choroid plexus tissue or perhaps by metaplasia from ependymal rests.

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