[Granulomatous change of the pituitary stalk caused by Rathke's cleft cyst: a case report].

We report a case of granulomatous change of the pituitary stalk caused by Rathke's cleft cyst. A 50-year-old woman complained of thirst and polyuria in December 2000. In January 2001, the patient was suspected to have diabetes inspidus, and MR Imaging showed a suprasellar mass of the pituitary stalk. The mass was totally resected by the trans-sylvian approach. Pathological diagnosis was Rathke's cleft cyst with subsequent granulomatous change. To our knowledge, there have been 11 cases of Rathke's cleft cyst and subsequent granulomatous change. In the literature, diabetes inspidus was not improved by surgical procedures. However, we suggest that the mass should be totally resected, because some cases in literature showed visual disturbance or hypo-pituitarism under observation.