Perineural spread of skin cancer presenting as diplopia

• Published in: Canadian Medical Association journal (CMAJ) Vol. 190; no. 1; pp. E13 - E16
• Main Authors: Mullen, Sarah J, Coret-Simon, Judith, Rodriguez, Amadeo R
• Format: Journal Article
• Language: English
• Published: Canada Joule Inc 08.01.2018; CMA Impact, Inc
• Subjects: Aged, 80 and over; Cancer therapies; CAT scans; Diagnosis; Diplopia; Diplopia - etiology; Eyes & eyesight; Female; Head & neck cancer; Humans; Magnetic Resonance Imaging - methods; Medical imaging; NMR; Nuclear magnetic resonance; Pain; Patients; Peripheral Nerves - physiopathology; Practice; Risk factors; Sinuses; Skin cancer; Skin Neoplasms - complications; Skin Neoplasms - diagnosis; Surgery; Tomography, X-Ray Computed - methods
• ISSN: 0820-3946; 1488-2329
• DOI: 10.1503/cmaj.170671

An 86-year-old woman tripped and fell on the sidewalk, hitting the front of her head. She did not lose consciousness, but diplopia developed. She presented to the emergency department where a noncontrast computed tomography (CT) scan of the head was within normal limits, and she was referred to the ophthalmology service. During ophthalmologic consultation, the patient stated she had primary hypothyroidism and osteoporosis. Her only medication was levothyroxine. Her main concern was binocular vertical diplopia that increased on downgaze, along with mild periorbital pain. Perineural spread of malignant growth is the migration of tumour cells from a primary site along any of the three layers of a nerve (epineurium, perineurium, endoneurium). This unusual means of tumour extension is distinct from spread through vascular and lymphatic channels. The mechanisms underlying this phenomenon are poorly understood. It was initially postulated that neural sheaths provided planes of relatively low resistance for growth of tumour cells.