Recurrent liponeurocytoma: A case report and systematic review of the literature

Abstract

Background: Liponeurocytomas are rare neurocytic neoplasms that most often arise in the posterior fossa and affect individuals in the third and fifth decades of life. Most reported cases of this unique tumor in the literature have described a favorable clinical prognosis without recurrence. However, increasing reports of recurrent cases prompted the World Health Organization, in 2016, to recategorize the tumor from Grade I to the less favorable Grade II classification. We conducted a systematic review to identify recurrent cases of this unique tumor and to summarize differences between the primary and recurrent cases of liponeurocytoma.

Methods: A systematic review exploring recurrent liponeurocytoma cases was conducted by searching the PubMed, Google Scholar, and Scopus databases for articles in English. Abstracts from articles were read and selected for full-text review according to a priori criteria. Relevant full-text articles were analyzed for symptoms, imaging, location, histological, pathological, treatment, and recurrence-free time between the primary and recurrent cases.

Results: Of 4392 articles, 15 articles accounting for 18 patients were included (level of evidence: IV) in the study. Recurrence-free time decreased from an average of 82 months between the primary tumor resection to first recurrence to 31.3 months between the first and second recurrence. Recurrent tumors demonstrated increased pleomorphic neural cells, necrosis, vascular proliferation, and MIB-1 index when compared to the primary tumor. Several cases also demonstrated decreased lipidizing components when compared to the primary tumor, further indicating increased dedifferentiation. The primary treatment for this tumor was surgical resection with occasional adjunctive radiotherapy.

Conclusion: Recurrent cases of liponeurocytoma have features of increased malignant proliferation compared to the primary cases. The standard treatment for these primary and recurrent tumors is gross total resection. The role of adjunctive radiotherapy remains a matter of debate.

Keywords: Liponeurocytoma; Neurocytic neoplasm; Recurrent; Systematic review.

Figure 1:

Magnetic resonance imaging demonstrates (a-d) presumptive recurrent liponeurocytoma (white arrow) as a heterogeneous solid and cystic mass in the left cerebellum abutting the left sigmoid sinus. (a-c) On axial, coronal, and sagittal T1-weighted imaging the lesion was isointense to the cortex with areas of hypointensity (not shown) with heterogeneous enhancement. The tumor was well marginated with minimal edema and without obstructive hydrocephalus. (d) Axial T2-weighted imaging shows heterogeneous hyperintensity of the tumor. Postoperative T1 axial, coronal, and sagittal (e-g); and T2 axial (h) images show complete resection of the mass.

Figure 2:

Histopathologic slides of the first recurrent liponeurocytoma. (a) Low magnification of the specimen shows large multifocal fat droplets intermixed with neurocytic cells and focal vascular proliferation. (b) High magnification shows detail of the monotonous nature of the neurocytic cells.

Figure 3:

Magnetic resonance imaging (MRI) demonstrates (a-d) recurrence of the liponeurocytoma (white arrow) occupying the left cerebellum. (a-c) On axial, coronal, and sagittal T1-weighted imaging, the lesion was hyperintense compared with the cortex. The tumor was well marginated without edema or obstructive hydrocephalus. (d) Axial T2-weighted imaging of the tumor is isointense to the cortex (not shown), with increased heterogeneous enhancement as compared to the initial recurrence. Postoperative T1 axial, coronal, and sagittal (e-g); and T2 axial (h) MRI images demonstrate no radiographic evidence of residual disease.

Figure 4:

Histopathologic slides of the second recurrent liponeurocytoma (a) show small, microscopic collections of fat with increased vascularity and cellularity compared to the first recurrent tumor. (b) Small tumor cells with mixed lipomatous differentiated neoplastic cells express synaptophysin. (c) Axons of the surrounding central nervous system tissue express neurofilament. (d) The Ki-67 proliferation index (as determined by MIB-1 staining) is 7.4%.

Figure 5:

PRISMA flowchart. This flowchart delineates the search and review process used to identify and select articles for inclusion in this study.