Facial paralysis following a fine needle aspiration of a benign parotid gland mass

Report of facial nerve paralysis following parotid fine needle aspiration. A 90-year-old male presented with a 2-month history of a painless right parotid gland mass. Computed tomography demonstrated a 2 cm, slightly hyperattenuating nodule in the superficial right parotid. He underwent two fine needle aspiration (FNA) biopsies, the first of which was non-diagnostic and the second suggestive of a pleomorphic adenoma. After the first FNA, he developed right lower eyelid and nasolabial fold weakness. He underwent a superficial parotidectomy, where the mass was noted to be cystic and densely adherent to the zygomatic branch of the facial nerve. Given the branch was already non-functional, it was sacrificed due to concerns for nerve involvement and to allow for complete removal of the mass. Final pathology was suggestive of an inflammatory or infectious etiology with no evidence of malignancy. Compression, fibrosis, and acute hemorrhage was seen in adjacent nerve branches on histopathology. Facial nerve paralysis from FNA of parotid neoplasms is extremely rare and has only been reported in association with hematoma formation, where paralysis was temporary. In this case, no hematoma was identified, and the paralysis persisted. The nerve was sacrificed during surgery given it was non-functional and inseparable from the mass, which was ultimately benign. This rare adverse outcome is important to recognize given its significant clinical implications.