[Clinicopathologic features of infant dysembryoplastic neuroepithelial tumor: a case report and literature review].

Dysembryoplastic neuroepithelial tumor (DNT) has traditionally been viewed as rare benign tumors that present with seizure widely considered curable with surgery alone. Most DNTs occur in childhood and young adults. However, rare reported cases occur in infants. This paper reported an infant case of DNT and its diagnosis, differential diagnosis, treatment, molecular features and prognosis based on the review of current literatures. The age onset of this patient was only 11 months old. The clinical manifestations were partial seizures and the imaging data untypical; CT and MRI were all supportive of astrocytoma. Typical glioneuronal element histologic features could be seen, which contained oligodendrocyte-like cells attached to bundles of axons and neurons floating in a myxoid interstitial fluid. Meanwhile, some atypical regions could also be seen. These atypical regions showed a mixture of oligodendrocyte-like cells and neurons without a myxoid interstitial fluid, which were easily misdiagnosed. The BRAF(V600E) mutation was not detected. This patient had a good response to drug therapy. Totally surgical resection of the tumor was conducted. The patient had been seizures free for 6 months. In conclusion, DNT is a rare and well prognostic tumor (WHO grade I), which most often arise in children in the setting of medically refractory epilepsy. The most common tumor location was temporal. Because clinical symptoms, imaging and histological features of DNT and other low-grade gliomas broadly overlap such as ganglioglioma, pilocytic astrocytomas and oligodendroglioma et al., differential diagnosis should be made carefully. The glioneuronal element was the histopathological hallmark of DNT. In addition, some untypical regions should also be called attention. Although BRAF(V600E) mutation didn't exist in this case, it played a role in differential diagnosis because it has been previously recorded that BRAF(V600E) mutation was a common feature of DNT. Infant patients have their own characteristics. For example, drug therapy worked well and the imaging data was untypical. Doctors should improve the understanding of this disease to avoid unnecessary radiotherapy or chemotherapy.