INCIDENCE AND HISTOLOGY OF HUMAN ACCESSORY PAROTID-GLANDS

The parotid glands of 228 Japanese human cadavers were examined to det ermine the incidence and histological features of accessory parotid gl ands. The incidence was found to be 56% with no differences between ri ght and left sides or between sexes. Thirty parotid glands and their a ssociated accessory glands were examined histologically: eight of thes e accessory glands were found to be mixed secretory glands (i.e., cont aining both serous and mucous acini). Thus, the pattern of differentia tion of a significant fraction of accessory glands differs from that o f the am parotid gland: it appears that mixed acini, present in the ea rly stages of development, persist into later life, and their presence may be related to tumors developing at these sites.