Case report: Central liponeurocytoma

Surgical management and clinical outcomes of cerebellar liponeurocytomas-a report of seven cases and a pooled analysis of individual patient data

Cerebellar liponeurocytomas (CLPNs) are very rare, with very few studies on this disease. Their treatment protocol also remains unclear. To better understand the disease, we reviewed the clinical features and outcomes, and proposed a treatment protocol based on previously reported cases as well as cases from our institute. The clinical data were obtained from seven patients with pathologically confirmed CLPNs, who underwent surgical treatment at our institute between November 2011 and June 2021. We also reviewed the relevant literature and 75 patients with CLPNs were identified between September 1993 and June 2021. Risk factors for progression-free survival (PFS) were evaluated in the pooled cohort. Our cohort included four males and three females, with a mean age of 43.9 ± 14.5 years (range: 29-64 years). CLPNs were located in the lateral ventricle in three cases and in the cerebellum in four cases. All seven cases achieved gross total resection (GTR) and radiotherapy was administered to two cases. After a mean follow-up of 44.9 ± 44.4 months, all patients remained well, with no recurrence or death. Among the 75 patients reported in the literature, 35 were males and 40 were females, with a mean age of 46.2 ± 13.6 years (range: 6-77 years). Biopsy, GTR, and non-GTR were achieved in one (1.3%), 50 (66.7%), and 24 (32%) patients, respectively. Radiotherapy was administered to 16 cases and chemotherapy was administered to only one case. After a mean follow-up of 47.5 ± 51.5 months, three patients died and tumor recurrence occurred in 17 patients. Multivariate Cox analysis revealed that non-GTR predicted a poor PFS (p = 0.020), and postoperative radiotherapy could not prolong PFS (p = 0.708). Kaplan-Meier analysis also showed that GTR was significantly associated with longer PFS (p = 0.008), and postoperative radiotherapy could not prolong PFS (p = 0.707). PFS rates at 1, 5, 10 years were 92.7%, 78.0%, 23.8% respectively. CLPNs are very rare brain tumors. Although they have favorable clinical prognosis, the recurrence is relatively high. GTR should be the first choice for treatment and close follow-up is necessary. Postoperative radiotherapy could not improve PFS in this study. A larger cohort is needed to verify our findings.

Lateral ventricular liponeurocytoma: Review of literature and case illustration

BACKGROUND

Liponeurocytoma is an uncommon tumor of the central nervous system. It is very rare for this tumor to originate within the lateral ventricle. In the context of the rarity of this tumor entity, this review article aims to summarize the clinical, radiological, and pathological features of lateral ventricular liponeurocytoma to facilitate its diagnosis and management.

METHODS

Here, we conduct a systematic literature review using the Pubmed, Scopus, and Cochrane Library database for all cases of lateral ventricular liponeurocytoma. A case illustration complements this review.

RESULTS

The described cases from 1997 onward include 14 cases that have been published in full papers in the English literature. Six additional cases are reported in short English abstracts in full non-English papers, and one case was described in a central neurocytoma report. There is a definite male predominance of 70% (14 male) and a mean age of 37 years (range 24-62). Heterogenous enhancement and signals in magnetic resonant images (MRI) are the radiological characteristics. In all reported cases, the presence of lipocytes and fat vacuoles is considered the paramount histopathological feature. Total surgical resection was achieved in 80% (12 out of 15) of the cases. Only two cases (including ours) received radiation therapy. Recurrence was seen in two patients during follow-up that was treated by radiation therapy in one and surgery in the other. The proliferation index is mostly below 5% in all cases, with the Ki-67 range between<1% to 10%.

CONCLUSIONS

Lateral ventricular liponeurocytoma has been treated effectively by surgical resection in a limited number of cases. The decision for radiation therapy is based on a high proliferation index and tumor recurrence.

Histology and molecular aspects of central neurocytoma

Central neurocytoma (CN) is a well-differentiated tumor of neural cells occurring within the ventricles. It is composed of monomorphic cells with round, regular nuclei within clear cytoplasm and must be distinguished from other clear cell tumors. Immunohistochemical markers of CN that aid in diagnosis include synaptophysin and neuronal nuclear antigen. The molecular biology of these tumors is becoming increasingly elucidated, particularly with the use of microarray analyses. Several oncogenic pathways have been suggested by these studies. Although progress continues to be made, knowledge of CN has yet to dictate targeted therapies in treating patients with these tumors.

Gamma knife radiosurgery for cranial neurocytomas

Gamma-knife surgery may be an effective alternative for treatment of central neurocytomas owing to its relative safety compared with conventional radiotherapy. In this paper we present results of gamma-knife treatment (GKS) of residual or recurrent neurocytomas. Twenty-two patients (14 female, 8 male) with recurrent or residual neurocytomas who underwent GKS were included. Diagnosis was based on histological findings. The proliferative potential of the tumors was examined by immunostaining with MIB-1 antibody, which is specific for detection of Ki-67 antigen. Tumor volume was determined by using post-gadolinium magnetic resonance images. After GKS treatment, MR imaging was scheduled at three-month intervals in the first year, at six months intervals in the second year, and yearly thereafter. Histopathological diagnoses were: 18 cases of central neurocytomas, two liponeurocytomas, one cerebral neurocytoma and one cerebellar neurocytoma. The MIB1 labeling index (LI) varied from 0 to 5.7%. Marked reduction in tumor volume was seen in 15 patients. In six patients, the tumor volume remained unchanged, and progression was observed for one patient. No complications because of GKS were noted. Shrinking effect on tumor volume increased with increasing duration of follow-up. On the other hand, high MIB labeling index did not seem to have an effect on tumor response to GKS treatment. Findings of this study suggest that GKS is an effective and safe treatment alternative for residual or recurrent neurocytomas. However, its effectiveness should be confirmed with larger studies.

A clinicopathological, immunohistochemical and neuroradiological study of eight patients with central neurocytoma

Central neurocytomas are low-grade tumors of neuronal origin located in the lateral ventricle that present predominantly with raised intracranial pressure. In this retrospective study, we investigated the clinical, radiological, histopathological and immunohistochemical features of eight patients (seven males and one female; age range 16-61 years; mean=35.1 years) with neurocytoma. Raised intracranial pressure was the most common presenting feature. In addition, one patient presented with marked visual deterioration and one presented with a visual field defect. All lesions were located in the lateral ventricle (right lateral ventricle: four patients, left lateral ventricle: three patients, both ventricles: one patients). Radiology showed marked intratumoral calcification in two patients. Total microsurgical excision was achieved in seven patients. Histopathology showed sheets of monotonously small-to-medium-sized neoplastic cells with uniform round-to-oval nuclei and inconspicuous nucleoli. Immunohistochemistry was positive for synaptophysin and neuron-specific enolase (NSE) in all tumors, and glial fibrillary acidic protein was focally positive in two patients. One patient had lipomatous differentiation within the tumor. No recurrence was noted in any of our patients until the last follow-up; however, there were two deaths in our series.