Paediatric Embryonal Tumours in Multilayered Rosettes Presenting as a Low Grade Glioma- An Unusual Case Report

Abstract

Paediatric Embryonal Tumours in Multilayered Rosettes (ETMR) are rare aggressive tumours with poor survival statistics, defined in 2016 by World Health Organisation (WHO) classification of brain tumours. The tumours have a characteristic radiological appearance on Magnetic Resonance Imaging (MRI) of the brain, which is easily decipherable. This combined with a clinical picture of raised intracranial pressure symptoms, seizures and rapidly progressive new onset neurological deficits make the diagnosis fairly obvious. The final confirmation of the diagnosis is done by immunohistochemical analysis of the C19Myc gene alteration. Rarely, certain radiological presentations are uncharacteristic and resemble other more benign pathologies with overlapping clinical presentations. This can be misleading, as ETMRs require aggressive surgery followed by adjuvant chemotherapy and radiation to ensure best possible survival. We present such a case report of what appeared to be a low-grade glioma in the frontal lobe. This tumour presented with one episode of generalised tonic clonic seizures not unusual as a presenting complaint in low-grade gliomas per se. Surgical debulking under ultrasonic guidance was done and the specimen was sent to histopathological analysis. The histopathological analysis showed a surprise ETMR diagnosis which was sent for confirmation to two other centers. This case report highlights the need to keep ETMRs as a rare differential diagnosis for even low-grade gliomas of the brain, thereby allowing accurate prognostication only after histopathological and immunohistochemical assessment. We present a brief literature review on unusual presentations of ETMRs reported in literature to further illustrate the chimeric nature of this rare disease.