A very rare adrenal tumor, but lethal & fully curable (the exact kind of diagnosis we hate to miss). Half of patients have sustained hypertension, usually hard to control. The others have paroxysmal surges of epinephrine which cause intermittent episodes of headache, generalized sweating, & palpitations. If you see hypertensive changes in the optic fundi of patients with normal blood pressure on a given day, suspect a pheo.
For patients with a classic symptom complex, not present during your visit, have them drop in on a day the headache recurs for a blood pressure check. If their pressure had been normal one day, and 200/110 the next, suspect a pheo.
See posting “Recurrent Headaches.”