NEURENTERIC CYST ARISING IN THE HIGH CONVEXITY PARIETAL LESION

Abstract

Supratentorial neurenteric cysts (NC) are rare; only 16 cases were reported previously, the majority of which were located in the anterior fossa or in the deep midline structure. We report a case of NC arising in the high convexity parietal lesion and briefly discuss the histogenesis of NC in such an unusual location. A 63-year-old man presented with a 1-month history of progressive headache and dizziness. Computed tomographic and magnetic resonance imaging scans demonstrated a 4 x 5 x 5 cm extra-axial cystic lesion in the right parietal convexity adjacent to the sagittal sinus without contrast enhancement. A translucent thin-walled cyst containing a milky-white fluid was partially excised via a right parietal craniotomy. The cyst wall was composed of a thin fibroconnective tissue lined by a single layer of ciliated columnar epithelial cells and pseudostratified columnar epithelium. Mucous-secreting goblet cells of epithelial lining reacted to periodic acid-Shiff staining. The internal epithelial cells were immunoreactive to cytokeratin and epithelial membrane antigen, but not to carcinoembryonic antigen, glial fibrillary acidic protein, or S-100 protein. A follow-up magnetic resonance imaging scan taken 6 months later showed resolution of mass effect without evidence of cyst recurrence. The patient was discharged home in excellent condition. A case of NC arising in the high convexity parietal lesion is described. Supratentorial NCs located far from the location of the primitive endoderm suggest the possibility that NCs could arise from ectopic endodermal tissue through an undetermined process of anomalous differentiation. Total surgical excision of the cyst wall and contents is the best treatment for the symptomatic cases. Subtotal or partial resection without injury to important neurovascular structures are reasonable alternatives, but long-term careful follow-up magnetic resonance imaging or computed tomography is necessary to monitor for recurrence of any residual lesion.