Malignant progression of an extraventricular neurocytoma arising from the VIIIth cranial nerve: A case report and literature review

Case report: A rare case of neurocytoma of the Vth cranial nerve

We report a case of neurocytoma originating from cranial nerve V. A 53-year-old female patient presented with a 20-day history of right frontotemporal facial paresthesia and pain. Magnetic resonance imaging (MRI) showed a 2.5-cm × 1.4-cm "dumbbell" enhancing lesion located in the cisternal segment of cranial nerve V with extension into Meckel's cave, and the signal characteristics were suggestive of trigeminal neurinoma. The lesion was resected through a subtemporal middle cranial fossa approach. Intraoperative findings revealed that the tumor originated from the cisternal segment of cranial nerve V and extended into Meckel's cave through the trigeminal foramen. No dural attachment was found. The tumor was debulked using sharp dissection and bipolar cautery under the microscope. Extraventricular neurocytomas (EVNs) are extremely rare tumors of the central nervous system. To date, only two cases of neurocytomas arising from cranial nerve VIII have been described. This paper summarizes the clinicopathological features of a case of neurocytoma originating from the cisternal segment of cranial nerve V with extension into Meckel's cave and expounds the relevant diagnoses and treatments, which may provide a practical clinical basis and experience for the diagnosis and treatment of EVN in the future.

The hidden hedgehog of the pituitary: hedgehog signaling in development, adulthood and disease of the hypothalamic-pituitary axis

Hedgehog signaling plays pivotal roles in embryonic development, adult homeostasis and tumorigenesis. However, its engagement in the pituitary gland has been long underestimated although Hedgehog signaling and pituitary embryogenic development are closely linked. Thus, deregulation of this signaling pathway during pituitary development results in malformation of the gland. Research of the last years further implicates a regulatory role of Hedgehog signaling in the function of the adult pituitary, because its activity is also interlinked with homeostasis, hormone production, and most likely also formation of neoplasms of the gland. The fact that this pathway can be efficiently targeted by validated therapeutic strategies makes it a promising candidate for treating pituitary diseases. We here summarize the current knowledge about the importance of Hedgehog signaling during pituitary development and review recent data that highlight the impact of Hedgehog signaling in the healthy and the diseased adult pituitary gland.

Cerebellar Neurocytoma with Excellent Response to Radiotherapy

BACKGROUND

Extraventricular neurocytoma (EVN) is a rare neurocytoma occurring in the brain parenchyma outside the ventricular system that shares similar biological behaviors and histopathologic characteristics with central neurocytoma. Reports of EVN localized in the brainstem and cerebellum are relatively uncommon. In addition, few cases with radiotherapy as the only treatment have been reported and their outcomes were unclear.

CASE DESCRIPTION

We report a case of pathologically confirmed EVN of the brainstem and cerebellum in a 43-year-old male who presented with unprovoked nausea and dizziness. The patient received radiotherapy only and showed a favorable outcome during the 2-year follow-up period.

CONCLUSIONS

These results suggest that patients with EVN who are treated with radiotherapy without surgery may have a favorable prognosis.