ラトケ嚢胞の病理、画像診断と外科治療　- 最新の知見-

抄録

Rathke cleft cysts (RCCs) are benign cystic lesions of the sella that arise from remnants of the embryonic Rathke residual pouch. RCCs are common incidental findings in 4-33% of autopsy cases and on imaging, and most remain asymptomatic. However, RCCs can become sufficiently large and rupture to cause severe headache, visual field defects and hypothalamic pituitary dysfunctions. Asymptomatic RCCs are typically followed by serial imaging, while symptomatic RCCs are managed by surgical decompression. Although a headache and the visual disturbance are improved by surgical treatment, the pituitary insufficiency is not often improved. It is thought that an irreversible disorder due to the local chronic inflammation involves the pituitary gland. MRI reveals well-demarcated homogenous lesions with variable intensity that is highly dependent on the protein concentration of cyst contents, which can range from clear, CSF-like fluid to thick, mucoid material. Rates of recurrence after surgical treatment range from 11 to 18 % in large series, and higher rates of recurrence are associated with inflammation and reactive squamous metaplasia in the cyst wall. As the natural history of RCCs remains unclear and the mechanism of progression of these cysts is not understood, it might be difficult to determine when we should do the intervention of the surgery.