Tumors of the Parotid Gland
TUMORS of the parotid gland are of particular interest for several reasons: first, despite years of intensive study since Virchow’s first description of the parotid mixed tumor in 1863, both their origin and pathologic classification remain subjects for speculation; secondly, the results of treatment, especially of malignant lesions, have been most discouraging; and finally, the treatment of even the most benign parotid neoplasm is complicated by its intimate relationship with the facial nerve and the threat of disfiguring facial paralysis. Recent contributions by Bailey,1 Brown,2 and Kirklin et al3 have contributed materially to the clarification of the problems and the establishment of sound, definite surgical therapy.
Anatomically, the parotid gland may be described as a dumb-bell shaped organ, with a large, superficial portion lying outside the mandible connected by a slender isthmus to smaller deep portion. McCormack et al4 have described a natural cleavage plane between these two lobes in which the facial nerve is found. The facial nerve leaves the skull via the stylomastoid foramen, and courses forward to enter the gland at its posterior margin, dividing almost immediately into two trunks which pass around the isthmus. Careful dissections of the nerve4 have shown some anastomosis between these two trunks around the isthmus in approximately three-quarters of the dissections. This would explain the lower than expected incidence of facial paralysis when individual nerve filaments are divided within the gland. A tongue of gland tissue extending forward along the parotid duct, often termed the accessory parotid gland, is of significance. . .