[A case of Rathke's cleft cyst in association with a ruptured aneurysm of the anterior cerebral artery mimicking pituitary apoplexy].

ABSTRACT

We present a rare case of a Rathke's cleft cyst in association with a ruptured aneurysm of the anterior cerebral artery (ACA). A 44-year-old man suffered from sudden onset of headache. Initial computed tomographic (CT) scan revealed a high-density mass lesion in the suprasellar region and a diffuse high-density area in the basal cistern. Using emergent magnetic resonance imaging (MRI), we found a cyst showed homogeneously high and iso-intensity on T1 and T2-weighted image, respectively. The cyst showed no enhancement of the cyst wall, but on Gd-DTPA, it was shown to compress the normal pituitary gland. Angiography showed an aneurysm at the A1 portion of the left ACA. Based on/these findings, we were able to diagnose Rathke's cleft cyst and a ruptured aneurysm. An operation was performed through the interhemispheric approach. The suprasellar cystic mass compressed the optic nerves and chiasm upward. Neck clipping of the aneurysm and opening of the cyst were performed. We confirmed the cause of the subarachnoid hemorrhage as being a ruptured aneurysm at the A1 portion of the left ACA. Histological diagnosis was Rathke's cleft cyst. Postoperative course was uneventful. There has been only one reported case of Rathke's cleft cyst in association with a ruptured aneurysm. When we encounter a case presenting subarachnoid hemorrhage with suprasellar mass and intracerebral aneurysm, we must discriminate between ruptured aneurysm and pituitary apoplexy in the acute stage as the cause of the subarachnoid hemorrhage. If the mass is Rathke's cleft cyst, we speculate that the cause of the subarachnoid hemorrhage is a ruptured aneurysm, because there are no reports of Rathke's cleft cyst with subarachnoid hemorrhage.