ABSTRACT
Hemifacial spasm (HFS) has been defined as consisting of brief clonic jerking movements
of the facial musculature, beginning in the orbicularis oculi with downward spreading
to other facial muscles. HFS, perhaps the most common of the abnormal involuntary
facial movements, has been classically ascribed to vascular loop compression at the
root exit zone of the facial nerve. Causes other than such vascular loops are rare
in the medical literature. Here we present three case studies in which the phenomenology
of the HFS was atypical in onset and evolution. Using these three patients as introduction
to the topic, we reviewed the literature of all cases of HFS with causes other than
the vascular loop. In these three cases, HFS was caused by (1) a parotid gland tumor,
(2) a cerebellopontine angle meningioma, and (3) an acoustic schwannoma. We also discuss
the radiological findings as well as possible differences in the genesis of HFS and
phenomenology in such cases and present recommendations on how to evaluate these patients.
KEYWORD
Hemifacial spasm - facial dyskinesias - psychogenic movement disorders - tumors
