Hypothalamic hamartoma associated with an arachnoid cyst.

A hypothalamic hamartoma associated with an arachnoid cyst in an 8-year-old boy is reported herein. He presented with precocious puberty, and neuroimaging studies demonstrated a solid mass in the prepontine cistern and a huge arachnoid cyst in the left cranial fossa. The mass appeared isointense to the surrounding cerebral cortex on T1-weighted magnetic resonance images, hyperintense on T2-weighted images, and was not enhanced after administration of Gd-DTPA. The patient underwent a left frontotemporal craniotomy and a cyst-peritoneal shunt was inserted. Histological features of the cyst wall and the mass were characteristic of an arachnoid cyst and hamartoma, respectively. While a hypothalamic hamartoma associated with an arachnoid cyst is rare, such a case may help clarify the geneses of both anomalous lesions.

Diagnosis of perineurial arachnoid cysts using computed tomography: technical and clinical considerations.

Perineurial arachnoid cysts are often multiple lesions that are usually found in the lumbosacral area. These cysts may cause compression of surrounding structures. Examination of the first, second and third sacral nerves should be performed on patients with prolonged symptoms of a herniated disc or cauda equina syndrome. Three cases are presented for which computed tomography provided accurate, noninvasive diagnosis. Perineurial cysts are often associated with asymptomatic herniated disc; thus, surgery on the disc with an underlying symptomatic cyst may result in a failed back syndrome.

Computed tomography of intra- and juxtasellar lesions. A radiological study of 108 cases.

During the first two years with the 160 X 160 matrix EMI scanner at Rigshospitalet, Copenhagen 108 consecutive patients referred with the suspicion of intra- or juxtasellar tumor were subjected to 166 computed tomography (CT) examinations. The X-ray attenuation and contrast enhancement patterns of the various lesions were analyzed. In general, it was difficult to correlate these parameters with the histopathological features. Arachnoid cysts, however, had typical low preinjection attenuation and no contrast enhancement. Chromophobe and eosinophilic pituitary adenomas rarely contained calcium and only in minute amounts, hardly visible on the polaroid pictures. Craniopharyngiomas and low grade suprasellar gliomas frequently contained large calcifications. Grade I gliomas, when located in the optic nerves or hypothalamus, showed significantly higher contrast enhancement than elsewhere in the brain. Three purely intrasellar adenomas were demonstrated with CT only. The diagnostic accuracy of CT was compared to that of carotid angiography, PEG and plain skull films in the lesions verified by initial operation (n = 32). CT gave the highest accuracy of the four methods, but the accuracy of CT differed statistically only from that of carotid angiography.