Suprasellar arachnoid cyst causing pituitary stalk compression and endocrine dysfunction in a child: MRI findings

Suprasellar arachnoid cysts are rare congenital lesions that may cause neurological, visual, or endocrine manifestations depending on their size and anatomical relationships with the hypothalamic–pituitary axis. Endocrine dysfunction in such cases is clinically significant as it may reflect hypothalamic–pituitary axis impairment and requires early recognition and management to prevent long-term sequelae We report the case of a 5-year-old girl presenting with endocrine abnormalities including growth hormone deficiency. Magnetic resonance imaging (MRI) of the hypothalamic–pituitary region revealed a well-defined suprasellar cystic lesion. The lesion demonstrated signal intensity identical to cerebrospinal fluid on all sequences and showed no enhancement after contrast administration. The cyst caused compression and rightward displacement of the pituitary stalk as well as superior displacement of the optic chiasm. Mild triventricular dilatation was also observed without evidence of transependymal cerebrospinal fluid resorption. The imaging findings were consistent with a suprasellar arachnoid cyst. This case highlights the importance of MRI in identifying suprasellar arachnoid cysts and evaluating their relationship with the hypothalamic–pituitary axis in pediatric patients presenting with endocrine dysfunction.