Endocrine Abstracts

JOINT631

Background: Macroprolactinomas and craniopharyngiomas are two sellar and suprasellar tumors that may share clinical and radiological similarities, often making differential diagnosis challenging.

Case Presentation: An 8-year-old boy presented with progressive frontal headache, visual loss, intermittent vomiting, but no galactorrhea or gynecomastia, without polyuric-polydipsic syndrome. He was not on any medication and had no family history of endocrinopathies. Clinically, with no growth delay, at Tanner stage G1P1. Brain MRI revealed a sellar and suprasellar mass 57 × 55 × 55 mm, with solid-cystic components without calcifications compressing the pituitary gland against the sellar floor, and involving the opto-chiasmatic cisterns, optic nerves, chiasm, with triventricular dilation. Biological tests showed a corticotropic deficiency. Prolactinemia was not initially assessed. The tumor was considered a likely craniopharyngioma. The patient underwent transsphenoidal surgery for tumor resection with hydrocortisone substitution. Immunostaining revealed neoplastic cells positive only for prolactin (100%) with a Ki-67 index of 4%. Three months post-surgery, MRI showed a 70% regression of the cystic component (22 cc vs 70 cc), with persistence of the solid component measuring 40 × 33 × 31 mm. The Prolactin level was 1736 ng/ml. The patient was started on Cabergoline 0.25 mg twice a week, gradually increased to 2 mg/week, Aiming to lower prolactin, shrink the tumor, improve visual function, and reverse corticotropic deficiency. Genetic testing for AIP mutation and Menin could not be performed due to unavailability.

Discussion: Unlike the craniopharyngioma, considered as the most common non-malignant sellar and suprasellar tumors in childhood, Pituitary adenomas are less common. Prolactinomas represent 50% of pediatric pituitary adenomas. Males tend to develop larger tumors with higher prolactin levels. The neuroradiological appearance of a non-homogeneous signal with a cystic component in prolactinomas can be mistaken for a craniopharyngioma. Genetic studies show that 10% of patients under 18 have mutations in AIP and MEN1 genes. The 2024 Consensus Guideline for the Diagnosis and Management of Pituitary Adenomas in Childhood and Adolescence recommends systematic serum prolactin measurement and the use of cabergoline as a first-line dopamine agonist therapy, even in the presence of visual disturbances or pituitary apoplexy. Treatment involves a progressive dose increase up to 1.5–2 mg per week. In cases of intolerance or resistance to high doses, surgery or radiotherapy may be considered as alternative options.

Conclusion: Craniopharyngiomas, though common in children, can mimic macroprolactinomas. Routine prolactin testing is crucial when assessing sellar masses to guide treatment before considering invasive surgery.