Perineural Spread of High-Grade Mucoepidermoid Malignancy Leading to Bells and Lateral Rectus Palsy

We present a case of high-grade mucoepidermoid carcinoma (MEC) with perinural spread into the base of the skull and infraorbital canal, leading to Lagophthalmos. An elderly woman in her late 60s presented with restricted mouth opening for the past six months, followed by a decrease in vision in the left eye. On investigation, a contrast CT scan showed a tumour mass in the parotid region with an extension into the infra-orbital canal. Fine-needle aspiration cytology (FNAC) of the lesion revealed metastatic epithelial carcinoma (MEC). In view of MEC, superficial parotidectomy was done. The specimen obtained was subjected to immunohistochemistry (IHC) analysis, which confirmed the lesion as a high-grade mucinous epithelial carcinoma. The surgery was followed by radiation therapy. The surgery was followed by radiation therapy. To summarise, perineural spread can cause patients to manifest neural impairment and associated complications such as facial/orbital palsy before the tumour is clinically evident. Findings such as loss of sensation and lagophthalmos lateral rectus palsy should alarm the clinician to suspect high-grade MEC, even if there is no evident clinical swelling.