Pathological features of peripheral facial paralysis caused by malignant tumour.

It has been reported that tumour invasion of the facial canal does not necessarily produce facial paralysis. The purpose of this paper is to present the facial nerve pathology in cases of facial paralysis caused by malignant neoplasms. Forty-seven temporal bones acquired from patients who died of malignant neoplasms were used for this analysis. Of the 47, 18 temporal bones (38.3%) had temporal bone metastasis or invasion. In 6 cases, the tumour destroyed the bony facial canals exposing the facial nerves to the invading tumour cells. The records of the patients showed that only half of the patients had facial paralysis. Those in whom tumour cells invaded the facial nerve beyond the epineural sheath had complete facial paralysis before death.