A partially ossified solid and cystic Rathke cleft cyst

Ratlike cleft cyst is considered to arise from the remnants of the Rathke pouch, and it consists of single cuboidal or columnar epithelium including cilia and goblet cells, which secrete mucus into the cyst. Magnetic resonance imaging characteristically shows a thin membranous cystic wall that enhances with Gd, and homogeneous intensity of the content suggesting fluid collection. Cases with an irregularly thickened and/or calcified cyst wall, presumably due to chronic inflammation of the wall, are rare. A 21-year-old woman presented with an extremely rare case of a solid and cystic Rathke cleft cyst with partial ossification, manifesting as bitemporal hemianopia. Magnetic resonance imaging showed a massive solid sellar lesion extending upward and compressing the optic chiasm and floor of the third ventricle. Transsphenoidal surgery was performed, resulting in total removal of the lesion and immediate recovery of visual function. Postoperative histological examination disclosed that the major part of the lesion consisted of various phases of clotting and granulation with significant fibrosis. Mature bone formation and abundant cholesterin clefts were also seen. Single cuboidal epithelium including goblet cells and cilia was found along this granulation, and the diagnosis was a Rathke cleft cyst. An ossified Rathke cleft cyst is extremely rare, and a solid Rathke cleft cyst has not before been reported. This case illustrates the extremely long and complex nature of this disease. (DOI: 10.3171/2009.10.JNS09826)