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Cerebellar liponeurocytoma (CL) is an unusual tumor, histologically composed of a mixture of small to medium-sized, rounded neurocytic cells and a variable lipomatous component. Although CL was originally considered as a subtype of medulloblastoma, subsequent molecular studies demonstrated that this tumor was a distinct entity, exhibiting the tumor protein p53 gene (TP53) missense mutations in 20% of cases, chromosome 17 deletion, and the absence of mutations in the adenomatous polyposis coli gene (APC), the protein patched homolog gene (PTCH), the kinase insert domain receptor gene (KDR), and the β-catenin gene (CTNNB). Apart from these molecular features, little is known about the pathogenesis and the genetic landscape of CL to date. In order to characterize the mutational landscape of CL and identify alterations that are driving tumorigenesis, we report a series of three cases, including one recurrent tumor, analysed by next-generation sequencing (NGS), which identified a total of 22 variants, of which four were missense mutations, nine were synonymous variants, and nine were located on intronic regions. In particular, DNA sequencing identified missense mutations in APC, KDR, and TP53 that could be implicated in promoting tumor progression and angiogenesis of CL. Furthermore, the NGS analysis revealed that recurrent CL did not have additional genetic changes compared with the primary tumor. Moreover, the high frequencies of detected mutations suggested that the identified alterations are germline variants. Indeed, an additional NGS on the genomic DNA obtained from one of the three patients confirmed the presence of the variants in the germline DNA. In conclusion, the obtained data support the hypothesis that CL is a distinct pathological entity that does not show specific somatic alterations driving tumorigenesis., (© 2022 Japanese Society of Neuropathology.)

Cerebellar liponeurocytoma (cLNC), categorized as a World Health Organization grade II tumor, is a rare neoplasm characterized by advanced neuronal/neurocytic differentiation and focal lipid accumulation in neuroepithelial tumor cells. However, the expression and genetic profiling of cLNC have been poorly studied. A 44-year-old woman with a three-year history of cerebellar ataxia and numbness in lower extremities underwent radiological examination revealing multiple contrast-enhancing tumors at the floor of the fourth ventricle and in the lower vermis, and spinal dissemination. The high uptake of 11 C-methionine in positron emission tomography (Met-PET) supported the preoperative cLNC diagnosis. Subtotal removal of the tumor around the obex and inferior vermis was performed. Histologically, the tumor was composed of small, uniform cells with round nuclei in a sheet-like fashion. Tumor cells were diffusely reactive for the neuronal markers synaptophysin and neurofilament. Vacuolate cells with a displacement of nuclei suggested the accumulation of lipid, which was further supported by immunohistochemical staining of S-100. These findings confirmed the diagnosis of cLNC. Next-generation sequencing of tumoral DNA detected a splice site mutation in the ATRX gene. Further reports of cLNC cases with detailed expression and genetic profiles are essential for precise diagnosis and clarifying the oncogenic pathway in cLNC., (© 2021. The Japan Society of Brain Tumor Pathology.)

Background: Cerebellar liponeurocytoma (cLNC) is a rare benign glioneuronal tumor with only ~60 cases reported since its first description in 1978. They have occurred largely as sporadic cases; however, familial cases with possible autosomal dominant inheritance have also been reported. Surgical excision has been considered the main modality of treatment, even for recurrent lesions. Uncertainties exist regarding the natural history, long-term outcomes, and optimal postoperative management and follow-up protocols for cLNC in general and multifocal cLNC in particular. Multifocality is exceedingly rare, with only 4 cases reported previously., Case Description: We present a case of multifocal cLNC in a young woman who had presented with progressive cerebellar symptoms of 5 months' duration. Her diagnostic neuroimaging evaluations revealed 2 asymmetric mass lesions (1 on each cerebellar hemisphere). We excised the larger lesion to relieve the mass effect and decided to monitor the smaller lesion radiologically. However, she developed a new lesion during the follow-up period and required adjuvant radiotherapy., Conclusion: Surgical excision forms the cornerstone of management of cLNCs. However, it is necessary to vigilantly monitor these patients owing to the high recurrence rates of cLNC despite the innocuous histologic features., (Copyright © 2018. Published by Elsevier Inc.)

Background: Cerebellar liponeurocytoma is a rare tumor of the central nervous system occurring mainly in the posterior fossa, which shows neuronal and variable astrocytic differentiation with foci of lipomatous differentiation. Liponeurocytoma develops in adult patients and is defined in the World Health Organization classification of 2016 as a rare benign grade II tumor., Case Presentation: A 39-year-old Italian man presented to our department suffering from headache and nausea. Magnetic resonance imaging revealed a right-sided cerebellar lesion showing poor contrast enhancement without an obstructive hydrocephalus. Surgery was indicated and total tumor resection was achieved. He was discharged without any neurological deficits. Histopathological examinations revealed a cerebellar liponeurocytoma. A neurological follow-up examination revealed no neurological deficit directly after surgery and 1 year later. Radiotherapy was recommended at the neurooncological board despite the total removal of the tumor, but our patient refused adjuvant radiotherapy. Magnetic resonance imaging of his neurocranium with and without contrast enhancement 48 hours after surgery and 15 months after surgery showed no residual tumor., Conclusions: Liponeurocytomas are rare benign tumors occurring in the majority of cases in the cerebellum. The therapy of choice is surgery. Postoperative radiotherapy has to be discussed individually, but seems to be sufficient if complete tumor resection is not achieved or in cases of a tumor recurrence.

We present a case of a rare neoplasm in a 77-year-old woman with previous oncological history, who developed a rapid onset of cerebellar symptoms. The neuroimaging detected a posterior fossa tumor suspected of meningioma which was completely resected soon after. Histologically the neoplasm had two components with different immunophenotype. One constituent was lobular, composed of monotonous mitotically active round cells with a predominant neuronal profile. The second, astrocytic component contained lipomatous cells intermixed with larger gemistocytic astrocytes. Fields of geographic necrosis as well as multifocal microvascular proliferation were observed. The Ki67 proliferation index was 12%. After two years of follow-up the patient remains free of symptoms and radiologic recurrence. The presented case of cerebellar liponeurocytoma is unusual in terms of its atypical histological features and prominent astrocytic component. The authors propose that the term 'lipomatous glioneuronal tumor' seems to be more appropriate for this type of lesion, considering its histologic spectrum and possible extracerebellar location.