Giant suprasellar arachnoid cyst presenting with precocious puberty.

To cite: Rao K, Levy ML, Crawford JR. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014205750 DESCRIPTION A 9-year-old boy presented with a several month history of precocious puberty. Two months before presentation he began to hear his voice gradually deepen; 3 weeks before presentation he noticed increased hair growth over his axillary and genital regions. Review of symptoms was negative for headache, nausea, vomiting or visual changes. In retrospect his growth chart revealed markedly accelerated weight and height over the last year to greater than the 90th centile and his genital examination was consistent with Tanner 3 staging. MRI revealed a giant 51×52×52 mm wellcircumscribed suprasellar arachnoid cyst extending to the third ventricular superiorly, the prepontine cistern inferiorly and the parasellar region bilaterally with obstruction of the foramen of Monro and associated ventriculomegaly (figure 1). No transependymal cerebrospinal flow was noted on T2-weighted sequences, suggesting compensated chronic ventriculomegaly. The arachnoid cyst exhibited significant mass effect on the pituitary infundibulum and on the optic chiasm. Given the degree of compression of the optic chiasm and pituitary together with evidence of precocious puberty, an endoscopic cyst fenestration was performed without complication. Suprasellar arachnoid cysts may present with endocrinopathies months to years prior to development of visual symptoms. Other presenting symptoms of arachnoid cysts include headache, seizures, visual loss, hydrocephalus or focal neurological deficits corresponding to cyst location. Asymptomatic patients whose arachnoid cysts are incidentally discovered should be observed with serial MRIs, endocrine testing and comprehensive ophthalmological evaluations. In those patients who are symptomatic, an endoscopic cyst fenestration is the preferred neurosurgical method.