CS-1 Cerebellar liponeurocytoma; Report of two cases with detailed metabolic, immunohistochemical, and genetic evaluations

Cerebellar liponeurocytoma (cLNC), World Health Organization grade II neoplasm, is a rare brain tumor characterized by advanced neuronal/neurocytic differentiation and focal lipid accumulation in neuroepithelial tumor cells. However, the expression and genetic profiling of cLNC, as well as metabolic imaging characteristics, have been poorly studied. Two patients with lower vermian tumors were operated on with telovelar approach. Moderate methionine uptake in positron emission tomography was observed in both cases. Histologically, the tumor was composed of small, uniform cells with round nuclei in a sheet-like fashion. Vacuolate cells with displacement of nuclei suggested the lipid accumulation, which was further supported by immunohistochemical staining of S-100. Although the extent of lipidization was relatively low compared with the reported cLNC cases, the immunohistochemical findings confirmed the diagnosis of cLNC. Next-generation sequencing of tumoral DNA in one case detected a splice site mutation of the ATRX gene, which is the first observation in the literature. Neither chemotherapy nor radiotherapy were administered postoperatively in both cases. In one case with spinal dissemination, residual tumor demonstrated progression 7 months after the resection. Long term follow-up data of cLNC cases with detailed expression and genetic profiles are essential for precise diagnosis and better understanding of the oncogenic pathway as well as the natural history of cLNC.

Cerebellar Liponeurocytoma Mimicking Medulloblastoma: Case Report of a Childhood and Literature Review

BackgroundCerebellar liponeurocytoma is a rare benign neoplasm of the central nervous system, which arises mainly in adult patients with only 3 cases reported in children. Due to its rarity, the diagnosis and treatment strategies for cerebellar liponeurocytoma remain unclear. The purpose of this study was to explore the epidemiology, clinical features, imaging findings, pathological characteristics, different diagnoses, treatment, and prognosis of cerebellar liponeurocytoma in juveniles.Case DescriptionA 5-year-old boy was admitted to the department of neurosurgery due to a 5-month history of headaches, nausea, vomiting, dizziness, dysphoria, as well as visual blurring associated with the peak of the headache. Magnetic resonance imaging showed a 4.9×5.4×6.2 cm mass located in the fourth ventricle and cerebellar vermis combined with hydrocephalus and periventricular edema. The mass was completely removed, and pathological examination indicated a cerebellar liponeurocytoma of the World Health Organization Grade II classification.ConclusionThe present study was the first to report a cerebellar liponeurocytoma with total tumor resection and adjuvant radiotherapy in a pediatric patient. Total tumor resection and postoperative radiotherapy together with close and long-term follow-up seem to be the optimal treatment strategy for juvenile patients. However, the side-effect of radiation needs to be considered.

Radiological and Clinical Findings of Multiple Cerebellar Liponeurocytoma: A Case Report

Background: Cerebellar liponeurocytoma is an extremely rare benign tumor which generally occurs in cerebellum and is almost always solitary. Multifocal cerebellar liponeurocytoma is exceedingly rare, only 8 cases has been reported so far. Herein we present the 9th case of multifocal cerebellar liponeurocytoma in a 70-year-old woman with the complete clinical course and comprehensive imaging findings.Case Presentation: A 70-year-old woman presented with a history of intermittent headache for 5 years. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain have been performed and suggested a diagnosis of teratoma based on the imaging findings. After the surgical resection of the lesion, histopathological and immunohistochemical analyses revealed neuronal, glial, and lipomatous components and confirmed the diagnosis of multifocal cerebellar liponeurocytoma after surgical resection. During the 2-year follow-up period, the patient showed no signs of recurrence or metastasis.Conclusion: We described the radiological characteristics and clinical course of an exceedingly rare case of multifocal cerebellar liponeurocytoma in the cerebellar vermis and temporal lobe. The clear multifocality makes this case unusual.

RADT-42. ADJUVANT RADIATION THERAPY FOR SUBTOTALLY RESECTED CEREBELLAR LIPONEUROCYTOMA

INTRODUCTION Classified as a benign glioneural tumor, cerebellar liponeurocytoma is a rare disease (fewer than 80 reported cases) and was upgraded from WHO grade I to grade II in 2007 due to its high recurrence rate. The authors report a case of definitive radiation therapy for recurrent subtotally resected cerebellar liponeurocytoma. METHODS An 80-year-old man having undergone seven resections for his left cerebellar liponeurocytoma without adjuvant therapy over the previous decade at outside institutions was referred for radiation therapy two months following his eighth resection, where gross total resection was limited by the lesion proximity to his brainstem resulting in a 2 cm residual left cerebellar lesion. Pathology revealed tumor cells strongly positive for synaptophysin and a Ki-67 labeling index < 1%. Due to the propensity of this disease to recur following resection, his entire resection cavity was treated with external beam radiation therapy (EBRT) to 46 Gy, followed by a 10 Gy boost to his residual disease yielding a total of 56 Gy to the residual disease. RESULTS Reimaging following the initial 46 Gy revealed the residual disease remained amenable (< 3 cm) to stereotactic radiosurgery (SRS), which was delivered via linear accelerator (10 Gy to the 80% isodose line) in a single fraction. Following EBRT + SRS, the patient responded well. At last follow-up, he has demonstrated no evidence of disease progression, brainstem-related morbidity or surgical incision-related morbidity. CONCLUSIONS The first reported case of SRS treatment of cerebellar liponeurocytoma as the culmination of a coordinated definitive plan beginning with EBRT supports the applicability and feasibility of this treatment strategy following subtotal resection. This case indicates that a radiation treatment plan similar to that for central neurocytoma may be an optimal strategy, and suggests that adjuvant radiation therapy following operative resection of this rare disease may be underutilized.

Glioneuronal Tumor With Features of Ganglioglioma and Neurocytoma Arising in the Fourth Ventricle: A Report of 2 Unusual Cases and a Review of Infratentorial Gangliogliomas

Infratentorial glioneuronal neoplasms are overall quite rare and are more commonly low-grade with surgical excision usually being curative. Multiple distinct histologic entities have been described including rosette-forming glioneuronal tumor, papillary glioneuronal tumor, neurocytoma, dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease), cerebellar liponeurocytoma, and ganglioglioma. While each of these entities has distinct findings, in some instances a tumor may demonstrate overlapping histologic features with mixed components. Herein, we report 2 unusual adult cases of a fourth ventricular glioneuronal tumor with features of ganglioglioma and neurocytoma, with one coming from a surgical resection and one found incidentally at autopsy. To the best of our knowledge, this specific histologic combination has not previously been described. As such, the clinical significance is unknown although in both cases the neoplasms were circumscribed and appeared to be low grade. The presence of the gangliogliomatous component was of particular interest since these are extremely rare occurrences in the fourth ventricle and we provide a comprehensive review of infratentorial gangliogliomas.