Non-malignant perineural spread of epithelial tissue in the orofacial region.

A 48 year-old male had two operations because of severe neuralgic pains in the region of the right infraorbital nerve. The first operative specimen consisted of connective tissue, striated muscle fibers and two myelinated nerve bundles, surrounded by a ring of well differentiated squamous epithelium. Initially the lesion was assumed to show perineural spread of cancer in this region. As the pain was not alleviated, a second operation was performed. The framework of the second specimen also consisted of connective tissue and muscle. It contained in addition an atheromalike cyst and some nerve bundles, ensheathed by well differentiated epithelial cells partly in a ring-, partly in a horseshoe-like pattern. The perineural epithelial sheaths could be traced to a rupture of the cyst, and to benign proliferation of its epithelial lining in the connective tissue and along the nerve bundles. Following the second operation the patient was relieved of his complaints. During the last five years he had repeated control examinations but no sign of malignant disease could be found; his state of health was perfect. Our finding of benign perineural spread of squamous epithelium has not been described previously. The nature of the so-called perineural lymph spaces is also discussed.