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Year : 2017  |  Volume : 65  |  Issue : 2  |  Page : 422--424

Cerebellar liponeurocytoma presenting as multifocal bilateral cerebellar hemispheric mass lesions

Laxminadh Sivaraju1, Saritha Aryan1, Nandita Ghosal2, Alangar S Hegde1,  
1 Department of Neurosurgery, Sri Sathya Sai Institute of Higher Medical Sciences, Bengaluru, Karnataka, India
2 Department of Pathology, Sri Sathya Sai Institute of Higher Medical Sciences, Bengaluru, Karnataka, India

Correspondence Address:
Dr. Laxminadh Sivaraju
Department of Neurosurgery, Sri Sathya Sai Institute of Higher Medical Sciences, Bengaluru - 560 066, Karnataka
India




How to cite this article:
Sivaraju L, Aryan S, Ghosal N, Hegde AS. Cerebellar liponeurocytoma presenting as multifocal bilateral cerebellar hemispheric mass lesions.Neurol India 2017;65:422-424


How to cite this URL:
Sivaraju L, Aryan S, Ghosal N, Hegde AS. Cerebellar liponeurocytoma presenting as multifocal bilateral cerebellar hemispheric mass lesions. Neurol India [serial online] 2017 [cited 2021 Oct 18 ];65:422-424
Available from: https://www.neurologyindia.com/text.asp?2017/65/2/422/201838


Full Text

Sir,

A 37-year-old male patient presented with headache, vomiting, and gait unsteadiness of 6 month duration. On examination, he had papilledema and gait ataxia. Magnetic resonance imaging (MRI) of the brain showed a mass lesion on the left side of the cerebellar vermis with extension to the cerebellar hemisphere, measuring 51 × 41 × 37 mm. It was reaching the fourth ventricle and causing mass effect on the brainstem and obstructive hydrocephalus. On T1-weighted images (WI), the tumor was isointense with hyperintense streaks. It was hyperintense on T2WI and fluid-attenuated inversion recovery (FLAIR) images and had no significant contrast enhancement. The lesion showed restricted diffusion and was hypointense on fat suppression sequences. MR spectroscopy showed elevated lipid and lactate peaks. Multiple similar smaller lesions were seen in both the cerebellar hemispheres. Screening of the spine was normal [Figure 1]a,[Figure 1]b,[Figure 1]c,[Figure 1]d,[Figure 1]e,[Figure 1]f,[Figure 1]g,[Figure 1]h. The differential diagnoses considered were metastases and medulloblastoma. He underwent a midline suboccipital craniotomy and near total excision of the vermian tumor. The tumor was seen on the surface of the inferior part of the vermis. It was grayish, soft-to-firm, vascular, with margins merging with the normal brain. Histopathology showed a cellular tumor arranged in lobular aggregates with monomorphic sheets, hyperchromatic cells and clear cytoplasm. There were scattered large cells with a vesicular nuclei, small nucleoli, and clear cytoplasm (intermediate ganglion differentiation). Features of microvascular proliferation, brisk mitotic activity (2–3/10 high power field [HPF]), foci of calcification, as well as lipomatous differentiation were noted. There was focal infiltration of the granular layer by the tumor cells. Intercellular neuropil-like matrix material with occasional foci of pseudorosettes were seen. Immunohistochemistry was positive for glial fibrillary acidic protein (GFAP) and synaptophysin in the tumor cells with a MIB-1 labelling index of approximately 6%. A diagnosis of cerebellar liponeurocytoma (CLN) was made based on the tumor showing a glioneuronal component with lipomatous areas [Figure 2]a,[Figure 2]b,[Figure 2]c,[Figure 2]d. The postoperative period was uneventful. Computed tomography (CT) of the brain showed no obvious residual vermian tumor; there was reduction in ventriculomegaly [Figure 2]e,[Figure 2]f. In view of multiplicity of the lesions and the excised tumor showing a relatively high MIB-index, he was referred to an Oncologist and underwent whole brain radiation therapy. He received 60 Gy radiation. At a follow-up of 2 years after the surgery, he was doing well. MRI did not show any recurrence of the vermian tumor or any new lesions; the remaining cerebellar hemispheric lesions had not grown in size.{Figure 1}{Figure 2}

More than 40 cases of CLN have been reported in the English literature.[1] CLN occurs mainly in the fourth and fifth decades of life with an equal sex distribution.[1],[2] Affected individuals present with raised intracranial pressure and cerebellar signs. CLN most commonly involves the cerebellar hemispheres, but may occur in the paramedian region or the vermis.[1] On a CT scan, the tumor is isodense or hypodense. On MR images, the tumor appears isointense to hypointense on T1WI and hyperintense on T2WI images. Contrast enhancement is variable.[1],[2] Fat-suppressed images show hypointensity of the lesion and aid in a preoperative diagnosis of liponeurocytoma. Multiple bilateral cerebellar hemispheric lesions, as seen in our case, occur very uncommonly. Differential diagnoses include medulloblastoma, oligodendroglioma, and ependymoma.[3] CLN is a glioneuronal tumor with lipidized neoplastic cells akin to mature adipocytes.[2] The tumor cells show cytoplasmic vacuolation and are arranged in sheets or lobules containing regular nuclei.[1] They do not generally show any mitotic activity, necrosis, or vascular endothelial proliferation.[1],[2] The tumor cells typically express neuronal markers such as synaptophysin and microtubule-associated protein 2 (MAP-2) and the glial marker glial fibrillary acidic protein (GFAP).[1],[2] The MIB-1 (Ki-67) labelling index is usually between 1% and 5%, but a few cases with a higher index have been reported.[1],[2] In view of the higher recurrence rates, CLN is classified as a grade II tumor in the revised 2007 World Health Organization classification.[1],[2]

It is difficult to differentiate these tumors histologically from a medulloblastoma and an oligodendroglioma.[4] CLN can mimic a medulloblastoma in their microscopic appearance. However, features of a high grade tumor such as a high mitotic index with increased cellularity and associated clinicoradiological findings of childhood predilection and drop metastases favor the diagnosis of a medulloblastoma.[5] Oligodendrocyte-like cells with a perinuclear halo and microvascular proliferation in CLNs can suggest a diagnosis of an oligodendroglioma.[4] Foci of pseudorosettes, as seen in our case, can point toward an anaplastic ependymoma. The key distinguishing feature in making the correct diagnosis of CLNs is its lipomatous differentiation.[5] The prognosis of CLNs is generally regarded as favorable and surgical excision is the recommended modality of treatment.[1] Radiotherapy is considered in cases of residual tumors or in tumors with a high proliferation index.[6],[7]

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References

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