Pediatric Giant Prolactinoma Presenting With Acute Obstructive Hydrocephalus and Intracranial Hypertension

Background: Pediatric prolactinomas (PP) are rare but represent 50% of all pediatric pituitary adenomas. Girls are affected more frequently than boys, although PP tend to be larger and more aggressive (earlier age, larger mass, and higher prolactin levels) in boys. Thus, microadenomas (tumors < 10 mm in diameter) are typical in females and macroadenomas (10–40 mm in diameter) are typical in males. Giant prolactinomas (> 40 mm in maximum diameter), an unusual subset of macroprolactinomas, are also commonly found in boys. In a large case series, the largest tumor volume reported was 93.5 cm(3). Here we report a giant prolactinoma in a female requiring V/P shunt for decompression. Clinical Case: A 16-year old female presented with 2 weeks of intractable headache, nausea and vomiting, vision impairment, and changes in balance described as running into stationary household objects. Historical review revealed primary amenorrhea and short stature. On initial exam, the patient had a right eye afferent pupillary defect, concern for loss of color vision, and bilateral optic nerve edema with blurred disc margins. Brain MRI showed a large lobulated mass centered in the suprasellar cistern, measuring approximately 6.4 x 5.8 x 5.7 cm with a tumor volume of 105 cm(3). There was extension superiorly, anteriorly, and laterally, with homogeneously enhancing and cystic components, and mass effect resulting in obstructive hydrocephalus. Differential diagnoses included craniopharyngioma, germinoma, and adenoma. Initial tests demonstrated prolactin of >2,000 ng/mL, with diluted result of 17,811.16 ng/mL. Morning fasting labs confirmed multiple anterior pituitary hormone deficiencies including central hypothyroidism, ACTH deficiency, GH deficiency, and hypogonadotropic hypogonadism. The patient was started on hydrocortisone and levothyroxine. Due to obstructive hydrocephalus and vision impairment, she underwent VP shunt placement for decompression. She was started on cabergoline for medical treatment of the tumor and did not require surgical resection. Repeat prolactin measurements have shown striking improvement (to 2,350 ng/ml, 824 ng/ml, and 152 ng/ml at 1 week, 1-month, and 2-month-follow-up, respectively) with central vision improved in both eyes, papilledema resolved, and resolution of headaches. Conclusion: Giant prolactinomas presenting with hydrocephalus and intracranial hypertension are very rare in pediatrics, especially in girls, and can vary greatly in mass characteristics and resulting hormone deficiencies. Our patient is unique with her large tumor volume and the extent of pituitary hormone deficiencies. Prolactin levels should be measured with all sellar masses, as this may prevent unnecessary invasive intervention and possibly provide prompt response to medical management.