Acute aseptic meningitis as the initial presentation of a macroprolactinoma

BACKGROUND: Meningitis is an uncommon complication of an untreated pituitary macroadenoma. Meningitis may occur in patients with macroadenomas who have undergone transsphenoidal surgery and radiotherapy and is usually associated with rhinorrhea. Less commonly, cerebrospinal fluid rhinorrhea has been reported as a complication of treatment of prolactinomas by dopamine agonists. Cerebrospinal fluid rhinorrhea in cases of untreated pituitary macroadenoma is reported only in isolated cases. Acute bacterial meningitis without rhinorrhea in patients with an untreated pituitary macroadenoma is an exceptional finding with only three previously reported cases. CASE PRESENTATION: A 31-year-old male was urgently admitted for headache, fever and visual loss. Neuroimaging disclosed an invasive pituitary lesion. Cerebrospinal fluid leakage was not clinically detected. Lumbar puncture showed acute meningitis. Blood tests revealed increased inflammatory markers, a serum prolactin of 9000 ng/ml (2.5-11 ng/ml) and panhypopituitarism. Intravenous antibiotics and hydrocortisone replacement therapy were initiated, leading to a favorable clinical outcome. An endoscopic transsphenoidal debulking procedure was performed, it showed that the sphenoid floor was destroyed and the sinus occluded by a massive tumor. CONCLUSIONS: Meningitis should be ruled out in patients with a pituitary mass who present with headache and increased inflammatory tests, even in the absence of rhinorrhea.