Supratentorial Intraparenchymal Neurenteric Cyst Treated by Neuroendoscopic Fenestration: A Case Report and Review of Literature

Neurenteric cysts (NCs) are rare benign congenital neoplasms in the central nervous system that originate from endodermal elements. NCs are more commonly located in the spine than in the brain. Although almost all intracranial NCs are found in the posterior fossa, some have reported supratentorial NCs. The complete excision of the cyst wall is suggested as a curative treatment; however, endoscopic treatment is less discussed. We present a supratentorial intraparenchymal NC in the frontal lobe treated by neuroendoscopic fenestration and review the literature regarding supratentorial NCs. A 43-year-old woman presenting with right hemiparesis and gait disturbance who was found to have a huge cystic lesion with calcification in her left frontal lobe underwent endoscopic fenestration to the ipsilateral lateral ventricle and biopsy. The histopathological diagnosis was consistent with NC. Postoperatively, her right hemiparesis and gait disturbance disappeared. Postoperative MRI showed shrinkage of the cyst. She was discharged without neurological deficits and no recurrence was seen 1 year after surgery. To the best of our knowledge, there have been no reports of a supratentorial intraparenchymal NC treated by neuroendoscopic fenestration. Minimally invasive treatments, such as neuroendoscopic cyst fenestration, can be considered depending on the location of the cyst.

Recurrence of a neurenteric cyst with malignant transformation in the foramen magnum after total resection. Case report

A 53-year-old man presented with recurrence of a neurenteric cyst with malignant transformation in the foramen magnum 3.5 years after total resection of the original tumor had been reported. For 2 years following the initial surgery, the patient had been in good condition, but then underwent ventriculoperitoneal shunt placement for intracranial hypertension. At the time there was no evidence of recurrence of the tumor on magnetic resonance (MR) images. One and one-half years later, he presented with headache and anorexia. A massive recurrent tumor was identified on MR images. The tumor was severely adhesive to the brainstem, cranial nerves, and vessels, allowing only partial resection. Histological examination of tumor specimens obtained during the first and second craniotomies indicated a malignant change from a typical neurenteric cyst with a one-layer epithelium in the first specimen to an adenocarcinoma with papillary proliferation in the second. The results of various immunohistochemical studies of the first specimen were typical of those of a neurenteric cyst. The second specimen displayed stronger staining of carbohydrate 19-9 and carcinoembryonic antigens than the initial specimen. The percentage of Ki-67 antigen (MIB-1)-positive cells increased from 0% in the first specimen to 6.7% in the second. To the authors' knowledge this is the first case in which malignant transformation has been demonstrated after total resection of a neurenteric cyst in the foramen magnum.