We report two patients with prolactin-secreting adenomas, SUNCT (short-lasting, unilateral neuralgiform headache attacks with conjunctival injection and tearing) syndrome, and bromocriptineinduced attacks.Case reports. Patient 1. A 40-year-old woman had her first headaches at age 27. The attacks consisted of a severe burning pain in the left parietal area, lasting 15 to 30 seconds. This was accompanied by conjunctival injection and tearing of the left eye, triggered by physical exercise or sexual activity. Three years later an amenorrhea-galactorrhea syndrome occurred. A CT scan revealed a pituitary adenoma, with suprasellar and left lateral extension, invading the left cavernous sinus (figure). Prolactinemia was 100 ng/mL (normal range, 9 to 20 ng/mL), without other endocrine abnormalities. An adenomectomy was performed but the tumor could not be removed entirely. Postoperatively, the prolactinemia normalized, then increased again during the following months. Bromocriptine treatment was started. Two hours after the first oral dose of 1.25 mg, the patient experienced repetitive severe headache attacks for 48 hours straight that were similar to those she had previously. The same phenomenon occurred after the intake of 0.25 mg lisuride and 0.5 mg cabergoline. After IM injections of 50 mg long-acting release bromocriptine, the attacks persisted for 7 days and were not prevented by carbamazepine or domperidone administered before the injections. After radiotherapy of the pituitary area and the left cavernous sinus was performed, the headaches became rare. Prolactin serum levels increased again after 2 years, although MRI showed total regression of the tumor. The patient was prescribed 75 mg/d quinagolide, a nonergot inhibitor of prolactin secretion. This did not trigger the neuralgiform attacks, and prolactinemia normalized after 6 months.Patient 2. A 24-year-old woman experienced for 4 months short attacks of severe left periorbital pain, lasting 15 to 30 seconds. This was accompanied by redness and tearing of the left eye, and a sensation of left nasal obstruction. These attacks usually occurred five to 10 times per hour for 2 or 3 hours, several times per week, and could be triggered by mild efforts such as bending or standing up. Four years later, she reported amenorrhea, and MRI showed a pituitary microadenoma with a left lateralization. Prolactinemia was 57 ng/mL. Bromocriptine treatment was started, and 3 to 4 hours after the first oral dose of 1.25 mg, she experienced a series of severe headache attacks for several hours that were similar to those she had previously. Bromocriptine treatment was interrupted and replaced by lisuride, which also triggered the attacks. A thyroid-stimulating hormone test to study the prolactin secretion was performed on three occasions, and each time induced severe bouts of attacks. Lisuride treatment was stopped after 1 year, and she experienced only rare headaches afterwards, usually triggered by movements. She underwent surgery for the microadenoma 10 months later.Discussion. T...