gms | German Medical Science

Objective: Cerebellar liponeurocytoma is a rare tumor of the cerebellum histologically characterized by advanced neuronal/neurocytic differentiation with focal lipidization. It typically develops in adults, and shows low proliferative potential. Recurrences have been reported in almost 50 % of cases, in most cases without histological features of malignant progression. But in contrast some tumor recurrences also show increased proliferative and mitotic activity. The WHO classification therefore assigns the cerebellar liponeurocytoma to WHO grade II. To date, less than 40 cases have been reported. Pathological diagnosis of cerebellar liponeurocytoma remains challenging with many tumors misdiagnosed for histologic mimics with high-grade character. The presented case highlights the main clinical, radiographic and pathological features.

Methods: We report the case of a 59 year old woman and describe the perioperative course and performed a detailed analysis of the molecular signature. We embedded our results in the available literature about cerebellar liponeurocytoma and discuss this case and the results in the light of the new WHO classification.

Results: A 59-year-old German woman presented at our department with a short history of persistent headache, vertigo and gait disturbances. Magnetic resonance imaging (MRI) showed a cerebellar tumor with positive gadolinium (Gd) enhancement in T1. The tumor was completely removed via a median suboccipital craniotomy opening of the foramen magnum. The early postoperative MRI did not detect any tumor remnants.The histological examination confirmed the diagnosis of a cerebellar liponeurocytoma WHO Grade II. To this date the patient did not receive any adjuvant treatment. The further pathological work up confirmed a negative 1p19q codeletion, a proliferative index of 5 %, GFAP positivity and MGMT promotor negativity. There was no IDH 1 Mutation in Codon 132. Further Illumina Human Methylation 450 (450k) Array was performed without any trendsetting chromosomal aberrations.

Conclusion: Medulloblastoma with lipidized cells is the most important differential diagnosis. The adipose tumor cells may also show a typical clustering comparable to liponeurocytoma. But a growth fraction of 15-40 % is not compatible in newly diagnosed liponeurocytoma. Knowing the fact that proliferative indices of up to 20 % were also shown in very few primary and recurrent liponeurocytoma. In addition genetic analysis revealed liponeurocytoma as a distinct tumor entity without a relation to medulloblastoma. The presence of TP53 mutations suggests they develop through different genetic pathways compared to neurocytoma also the cDNA expression profiles showed a relationship to this entity. The importance of accurate diagnosis should not be underestimated because of possible further therapeutic interventions and determination of the patient’s prognosis.