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CASE REPORT
Year : 2023 | Volume
: 50
| Issue : 1 | Page : 108-110
Cerebellar Liponeurocytoma: Report of a Rare Entity
Kritika Singh1, Ashvini Kolhe2, Naina Goel2
1 Department of Pathology, Dr. D. Y. Patil Medical College and Hospital, Navi Mumbai, Maharashtra, India
2 Department of Pathology, Seth G. S. Medical College and K. E. M Hospital, Mumbai, Maharashtra, India
Correspondence Address:
Kritika Singh
Department of Pathology, Dr. D. Y. Patil Medical College and Hospital, Ayyappa Road, Sector-5, Nerul, Navi Mumbai - 400 706, Maharashtra
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/jss.jss_130_22
Cerebellar liponeurocytoma is a rare clinicopathological entity, included in the 2000 World Health Organization (WHO) classification of tumors of the central nervous system in the category of glioneuronal tumors. These are WHO Grade II, slow-growing tumors in adults with known recurrences. To date, about 70 cases of liponeurocytomas have been reported. This tumor needs to be differentiated from oligodendroglioma as well as medulloblastoma which are more common and aggressive, requiring postoperative chemoradiation. A high index of suspicion is thus advocated for the diagnosis. We present one such case of this rare entity reported in our institute. A 42-year-old female presented with a 4-month history of headache, neck pain, reduced vision, and cerebellar signs. Imaging showed a midline lesion involving the cerebellar vermis and left lobe suggestive of anaplastic ependymoma/hemangioblastoma. The final diagnosis of cerebellar liponeurocytoma was rendered on routine histopathological examination supported by immunohistochemical analysis.
Keywords: Adipocytic, cerebellar liponeurocytoma, histopathology
Cerebellar liponeurocytoma is a rare central nervous system (CNS) neoplasm. Initially included as a distinct mixed glioneuronal Grade I entity in the 2000 World Health Organization (WHO) classification of CNS tumors, it was subsequently upgraded to WHO Grade II in 2007. This was in consideration of recurrences noted in almost half of the cases during their follow-up period.[1] This designation is still in use in the revised 2016 WHO classification.[2]
With about 73 cases reported in the literature, the clinical behavior and optimal treatment therapy of this tumor are still evolving and is under study.[3] In addition, clinical diagnosis becomes difficult due to the lack of typical imaging findings. It is important to differentiate these tumors on the basis of histopathological examination from their close mimics such as medulloblastomas and oligodendrogliomas as the management protocol is different.
We present here one such rare case of cerebellar liponeurocytoma that was reported in our institute.
Case ReportA 42-year-old female presented with a 4-month history of headache, neck pain, and blurred vision. On examination, her visual acuity in the left eye was finger counting at 4–6 feet and in the right eye, it was finger counting at 2–3 feet. Bilateral cerebellar signs were positive, left more than right. There were no other neurological deficits. Magnetic resonance imaging revealed a 3.3 cm × 3.2 cm × 2.3 cm hypointense lesion with focal altered signal intensity on T1-weighted imaging (WI). On T2WI, the lesion appeared hyperintense compared with the cortex, involving the left lobe and inferior vermis of the cerebellum, resulting in the compression of neural structures at the cervico-medullary junction. The lesion showed mild contrast enhancement [Figure 1].
Figure 1: MRI of the brain in T1W axial (a) and coronal plane (b) showing focal altered signal intensity lesion in midline involving the cerebellar vermis and adjacent left lobe. Tumor appears mildly hypointense causing cerebellar herniation with compression of cervico-medullary junction. In T2W Axial view, tumor is hyperintense to cortex (c). Minimal ill-defined contrast enhancement is seen (d). MRI: Magnetic resonance imagingThe patient underwent suboccipital midline craniotomy and excision of the tumor was done. Grossly, multiple irregular, gray-white fragments of tumor aggregating to 3.5 cm in diameter were received for the histopathology examination. Microscopic examination of hematoxylin and eosin-stained paraffin sections showed a cellular tumor composed of sheets and lobules of monomorphic cells having uniform round nuclei showing perinuclear clearing, lying against a fine fibrillary background. At places, the tumor cells showed adipocytic differentiation. Mitotic activity was not evident and there was no necrosis [Figure 2]. On immunohistochemistry, the tumor cells were positive for neuron-specific enolase (NSE) and synaptophysin demonstrating neurocytic differentiation. There was a focal expression of glial fibrillary acid protein (GFAP). Ki67/MIB-1 proliferative index was <1% [Figure 3].
Figure 2: Photomicrograph of H and E stained sections showing cellular tumor (arrow) arranged in sheets and lobules with overlying normal cerebellar foliage (a and b, ×100). Monomorphic round cells admixed with lipomatous cells (arrow) lying on a fine fibrillary background (c and d, ×400). H and E: Hematoxylin and Eosin
Figure 3: Immunohistochemistry stained sections showing tumor cell positivity with NSE, synaptophysin and GFAP. MIB-1 proliferative index <1%. NSE: Neuron specific enolase, GFAP: Glial fibrillary acid proteinThe immediate postoperative course was uneventful. However, the patient unfortunately was lost to long-term follow-up.
DiscussionCerebellar liponeurocytoma is a rare neoplasm that shows neuronal, variable glial, and lipomatous differentiation. It was first described by Bechtel et al. (1978) in a 44-year-old male and reported as “lipomatous medulloblastoma,” a posterior fossa neuroectodermal tumor that showed presence of focal adipose tissue. Ever since, these have been known by various names such as medullocytoma, lipidized medulloblastoma, and neurolipocytoma.[4],[5],[6]
Although the cerebellum is the most common location, these are also identified in the supratentorial region of the brain. Hence, the usage of the term “liponeurocytoma” is suggested.[7] A systematic review conducted by Gembruch et al. from 1978 to 2018 identified about 70 cases of liponeurocytoma, 80% of which were located in the posterior cranial fossa.[3] It commonly occurs in adults with a mean age of 40–50 years with a slight female predilection.[8],[9] Patients most often present with signs and symptoms of increased intracranial pressure, cerebellar signs, and/or visual complaints.
Absence of mitotic activity, necrosis, and endothelial proliferation point toward the low proliferative nature of these tumors and favorable prognosis. It may also have an aggressive course and have a high recurrence rate; hence, close follow-up is recommended. It is important to differentiate this tumor from its morphological mimics such as lipomatous variant of medulloblastoma, clear cell ependymoma, and oligodendroglioma.[8] Differentiation using immunohistochemistry panel is helpful. Since cerebellar liponeurocytomas are neurocytic tumors, they stain diffusely with NSE and synaptophysin while GFAP is only focally positive in reactive astrocytes, glial component and lipidized cells. Oligodendrogliomas are diffuse positive for Olig2, GFAP, and Isocitrate Dehydrogenase I (IDH1[R132H]) unlike cerebellar liponeurocytomas. Negativity for epithelial membrane antigen and S-100 helps differentiating them from ependymoma. Medulloblastomas are high-grade tumors that usually occur in younger age group and have a high Ki67/MIB-1 proliferative index. This tumor also does not have the same molecular genetic profile as its differentials. Recently, Wolf et al. suggested a familial predisposition with a possible autosomal pattern of inheritance, thus warranting the need for additional studies to identify the causal germline mutation and recommendation of family screening.[10] The current surgical treatment strategy appears to be a total radical resection. Due to its rarity and availability of limited data, the role of adjuvant radiation treatment is under discussion. Recurrence of the tumor has been commonly seen in cases where complete resection could not be achieved or those showing high mitosis/>10 Ki67 positive cells. In this select group of patients, radiotherapy can be favorable.[11],[12]
ConclusionCerebellar liponeurocytoma has distinctive morphological and immunophenotyping features with no specific genetic alterations detected till date. The available follow-up data indicate a favorable clinical outcome. Precise characterization of this tumor is important to avoid unnecessary adjuvant radio or chemotherapy.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Acknowledgment
The authors would like to thank Department of Neurosurgery under Dr.Atul Goel, Seth G. S. Medical College and K. E. M. Hospital, Parel, Mumbai.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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