A 55 year old man complains of progressive changes in his facial appearance over the last year, as noted by his wife and co-workers. He has also gained 15 kg of weight in that time.

Further questioning reveals a history of numbness and tingling in his fingers for the last 3 months, and intermittent headaches for the past 5 months. He has also gained a shoe size since the onset of symptoms.

His medical, surgical, and family histories are unremarkable. He does not smoke, and only drinks socially.