Neurenteric cysts, also known as enterogenous, endodermal, neuroenteric, respiratory, or bronchogenic cysts, are rare benign lesions of the central nervous system that are lined by endodermal cell-derived epithelium. 6, 13, 26 They are most frequently found in the intradural extramedullary space in the lower cervical and upper thoracic spine. 3, 10, 22 Intracranial neurenteric cysts are even rarer, with the majority located in the posterior fossa. 6, 8, 13, 14 Spinal neurenteric cysts are often

more »

... connected by a fibrous tract, fistula, or cleft to structures derived from the primitive gut in the thoracic or abdominal cavities and are commonly associated with vertebral anomalies such as vertebral body dysgenesis, split spinal cord malformations, hemivertebra, segmentation abnormalities, and spina bifida. 7, 12, 22, 24 This is not the case with intracranial neurenteric cysts. 6 Although the exact pathogenesis remains unknown, intracranial neurenteric cysts are thought to arise from a failure of dissolution of the transient neurenteric canal between the foregut or the respiratory buds and the notochord during notochordal development. 8,14,17 Posterior fossa neurenteric cysts constitute more than 90% of the intracranial form of these cysts, and they occur mostly along the midline. In a review by Bejjani, et al., 6 the most common locations of posterior fossa neurenteric cysts were anterior to the brainstem (51%) or within the fourth ventricle (21%). Also, 18% of the cysts extended into the cervical canal and 17% were located primarily in the CPA. Neurenteric cysts that are located in the anterior cervicomedullary junction are even rarer, and often require a skull base approach for adequate resection. 1, 12, 14, 16, 20, 21 We describe two cases of neurenteric cysts arising from the cervicomedullary junction that were resected via a far-lateral transcondylar approach. We discuss the surgical approach and operative nuances involved in removing these lesions, and we review the clinical presentation of neurenteric cysts in this region as well as the neuroimaging characteristics, histopathological findings, and surgical management. CASE REPORTS Case 1 History and Examination. This 46-year-old woman presented with pain in the right shoulder, right ear, and interscapular area. Results of the neurological examination were normal, with the exception of a markedly diminished gag reflex on the right side. A laryngoscopic examination performed in the otolaryngology service demonstrated normal vocal cord movement. Neurenteric cysts are rare benign lesions of the central nervous system that are lined by endodermal cell-derived epithelium. Although they occur mostly in the spine, they can occur intracranially, most often in the posterior fossa. Neurenteric cysts that are located in the anterior cervicomedullary junction are even rarer and often require a skull base approach for adequate resection. The authors describe two cases of neurenteric cysts arising from the cervicomedullary junction that were resected via a far-lateral transcondylar approach. They discuss the surgical approach and operative nuances involved in removing these lesions, and review the clinical presentation of neurenteric cysts in this region as well as the neuroimaging characteristics, histopathological findings, and surgical management. Intraoperative videos are presented. KEY WORDS • neurenteric cyst • enterogenous cyst • cervicomedullary junction • far-lateral transcondylar approach Neurosurg. Focus / Volume 19 / August, 2005 1 Abbreviations used in this paper: CPA = cerebellopontine angle; FLAIR = fluid-attenuated inversion-recovery; MR = magnetic resonance; VA = vertebral artery.