A Weak Presentation

Brain imaging from 2006 to 2014 were re-reviewed to look for cranial nerve enhancement, skull base lesions or leptomeningeal enhancement. All were negative with the exception of an enhancing right intraconal orbital mass. Biopsy of the right intraconal mass was performed. Pathology showed metastatic poorly differentiated squamous cell carcinoma. The final diagnosis is squamous cell carcinoma (SCCA) of the orbit with perineural invasion. Isolated orbital SCCA is rare, as the orbit does not normally contain squamous epithelial elements. More commonly, orbital SCCA arises via hematogenous spread from distant lesions or direct extension from paranasal sinuses, however this orbital tumor would not explain his other neurologic findings. Perineural spread is a well-recognized phenomenon in head and neck cancers, and SCCA is the most frequent neoplasm involved. Various mechanisms of perineural invasion have been postulated, including presence of nerve cell adhesion molecules and toll-like receptor 3 (TLR-3), however their role in perineural invasion associated with SCCA are not well defined. The reported incidence of perineural spread with squamous cell carcinoma of the head and neck is between 2-5%, with increasing risk associated with male gender, recurrent tumors > 2 cm, forehead location, and previous treatment. Because of their extensive subcutaneous distribution, the trigeminal and facial nerves are most commonly affected. Perineural spread most commonly presents with paresthesias, face pain, ptosis, diplopia, facial weakness, and ophthalmoplegia. The sensitivity of MRI in detecting perineural spread has been reported to be 95%. Nevertheless, perineural invasion can be missed without a high index of suspicion. Treatment guidelines for patients with perineural spread have not been established. Patients typically undergo surgery followed by radiation therapy. In the presence of perineural invasion, the five-year survival rate is thought to decrease by about 30%.