Mode of parotid involvement in external auditory canal carcinoma.

Until now, little was known about the mode of parotid involvement in external auditory canal (EAC) carcinoma. The incidence of parotid node metastasis and direct parotid invasion was examined in patients with EAC carcinoma. The study comprised 11 patients with squamous cell carcinomas (SCC) and 10 patients with adenoid cystic carcinomas (ACC). A retrospective review of the surgical specimens was undertaken with specific reference to parotid node metastasis and parotid invasion. Parotid node metastasis was noted only in two cases of advanced staged SCC, whereas none of the ACC patients showed parotid node metastasis. Direct parotid invasion occurred only in advanced staged SCC, however, it did occur in early stage ACC. Our data indicated that elective parotidectomy for control of occult parotid node metastasis is necessary only in advanced SCC carcinoma, whereas parotid management to secure adequate safety margins is mandatory for advanced SCC and all cases of ACC.