Dysembryoplastic neuroepithelial tumour in the cerebellum: case report and literature review

Posterior Fossa Dysembryoplastic Neuroepithelial Tumor: A Neuropathological Report

Dysembryoplastic neuroepithelial tumors (DNTs) are rare neoplastic entries of the central nervous system. Conventionally DNTs are with cortical location and predominantly occur in the temporal lobe associated with epilepsy. Subtentorial DNTs are rare entries. Herein we report a case of a two-year-old female with a DNT located in the cerebellum. The patient presented clinically with new onset gait instability, headaches and strabismus. Neuroradiology revealed a heterogenous, predominantly cystic lesion in the cerebellar vermis and left cerebellar hemisphere, which was interpreted as possible medulloblastoma based on the patient profile. Frozen section neuropathology was more suggestive of a low-grade glial tumor, with conventional histology and immunohistochemistry showing an admixture of glial and neuronal cells - a complex variety of DNT. Due to the histological appearance, differential diagnosis was required with other neuroglial tumors native to the posterior fossa, such as Lhermitte-Duclos disease. There have been several such published case reports, which, although of older patients, present with similar symptoms and neuropathological findings. The complexity of the neuropathological finding in posterior fossa DNTs can lead to future separation of this entry from conventional DNT, as was seen in the past with septum pellucidum DNT, now referred to as myxoid glioneuronal tumor.

A Constellation of Atypical Findings in a Nine-Year-Old Child With Dysembryoplastic Neuroepithelial Tumors: A Case Report and Review of the Literature

Dysembryoplastic neuroepithelial tumors (DNETs) are rare, generally benign, mixed neuronal-glial neoplasms occurring most often between 10 and 14 years of age. These lesions are classically cortically based and solitary, found preferentially in the temporal lobe, and most commonly present with seizures. On magnetic resonance imaging (MRI), these lesions are generally cystic and have variable contrast enhancement, which, when present, often involves the periphery. Rarely, lesions followed radiographically may demonstrate delayed contrast enhancement. Here, we present a case of multifocal DNETs involving the cerebellum that demonstrated delayed contrast enhancement. In addition, these occurred in a patient with Noonan syndrome (NS), a “RASopathy” disorder associated with low-grade glial and glioneuronal tumors. We present a summary of all previously reported cases of cerebellar DNETs. Our patient was successfully treated surgically and is doing well clinically, now one year status post his last procedure, and is being closely monitored with serial MRIs for progression. Gross total resection is often curative without adjuvant therapy for most DNETs. Our case emphasizes the importance of radiographic surveillance, as multifocality and recurrence may necessitate more than one procedure. Lastly, clinicians should be suspicious for DNETs and other low-grade glial tumors when treating patients with NS, acknowledging their predisposition for multifocal involvement and atypical presentations.

Dysembryoplastic Neuroepithelial Tumor of the Infratentorial Multiple Lesions: A Case Report and Review of the Literature

A dysembryoplastic neuroepithelial tumor (DNT) is a benign neoplasm that usually occurs in the supratentorial cerebral cortex. Here, we report a rare case of an infratentorial DNT in a 42-year-old woman who presented with dizziness and a gait disturbance. Magnetic resonance imaging of the lesion demonstrated hyperintensity on T2-weighted images and hypointensity on T1-weighted images of the left cerebellar hemisphere with a multifocal lesion. Macroscopically, the lesion appeared soft, avascular, and slightly torose at the cortical surface. Histologically, dysplastic disorganization of the cortex and floating neurons were observed. The pathological and immunochemical features of this case agree with the diagnosis of a DNT. The lesion partially included cortical heterotopia, which is a novel observation in an infratentorial DNT. On the basis of the previous reports, we discussed the surgical resection of the infratentorial DNT.