Ganglioneuroma of the sacral canal: an unusual location with MR imaging findings.

Ganglioneuroma is a rare, benign, slow-growing tumor arising from embryonic neural crest cells that differentiate into the sympathetic ganglia. Accordingly, it can occur anywhere along the sympathetic chain, from the clivus to the sacrum, although it is seen most commonly in the mediastinum, retroperitoneum, adrenal glands, and neck. Although involvement at the sacral level is uncommon, ganglioneuroma typically arises from the anterior surface of the sacrum, with presacral lesions occasionally extending through the sacral foramina into the sacral canal. Only two cases of ganglioneuroma confined to the sacral canal without presacral involvement have been reported in the literature, to the best our knowledge. On magnetic resonance imaging, ganglioneuroma usually demonstrates a low signal intensity on T1-weighted images, heterogeneous high signal intensity on T2-weighted images, and variable enhancement patterns. We report a case of sacral canal ganglioneuroma in a 72-year-old woman presenting with a fluid level which is a previously unreported imaging feature, to the best of our knowledge. The unusual patient age, location, and imaging characteristics of this patient's ganglioneuroma posed a diagnostic challenge. We also review previously reported cases of sacral canal ganglioneuroma and highlight the radiologic features, with particular emphasis on the presence of a fluid level.