Rathke's cleft cyst.

Rathke's cleft cysts are benign sellar and suprasellar lesions arising from epithelial remnants of Rathke's pouch with a peak incidence at 30-50 years of age. The majority are between 10 and 20mm in diameter and contain mucoid or gelatinous material encapsulated in a thin cyst wall of simple or pseudostratified cuboidal or columnar epithelium. Symptomatic cases are rare, but incidental lesions are found in 11% of unselected postmortem cases. The pathogenesis of these lesions is uncertain, but they may occasionally share histopathologic features with (papillary) craniopharyngiomas. The most common presenting symptoms include headaches, visual disturbance, and pituitary hormone abnormalities. MRI reveals well-demarcated homogenous lesions with variable intensity that is highly dependent on cyst contents, which can range from clear, CSF-like fluid to thick, mucoid material. Treatment is almost invariably surgical with the aim of draining the cyst contents and removing the surrounding capsule. The recurrence rate is uncertain due to a lack of studies with long follow-up periods, but risk factors associated with increased likelihood of recurrence include cyst size, presence of squamous metaplasia of the cyst wall, incomplete resection or intraoperative CSF leak, and the need for an abdominal fat graft or sellar packing.