How this GP missed an obvious diagnosis for 10 years

Since medicine is such a relationship-based vocation, I find myself very often looking at my patients as people and not as clinical subjects. I have to keep reminding myself to do both.
I saw a cancer survivor recently whom I have known for 10 years. I had referred him to a neurologist because of an atypical tremor. The neurologist diagnosed my patient with Parkinson’s disease, but also pointed out that he had Horner’s Syndrome (droopy upper eyelid, small pupil and sunken in eye).
Was I ever humbled! I had seen the droopy upper right eyelid since I first met the man, but never had reason or, rather, been medically curious enough to check his pupils — the pupil on the droopy lid side is indeed smaller.
I have seen Horner’s Syndrome a few times, twice in the context of sinus cancer. One case was a woman who ended up with surgery that exposed the back of her eye socket and the back wall of her maxillary sinus, just like the pictures in my old anatomy books; the other was my own cat, who did not go through such radical surgery. Both died from their disease.