CASE REPORT J Neurosurg Pediatr 26:34–37, 2020 Dysembryoplastic neuroepithelial tumor presenting as a hypothalamic hamartoma in a child with gelastic seizures: case report Yuxiang Cai, MD, Yanjin Wang, MD, and Zhiquan Yang, MD Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China Dysembryoplastic neuroepithelial tumors (DNETs) are benign intracranial tumors of neuroglial origin, mostly located in the supratentorial regions and particularly in the temporal lobe. Few cases of DNETs in the hypothalamus have been described. The authors present the case of a DNET in the hypothalamus. The 5-year-old girl with complaints of limb and gelastic seizures was admitted to the neurosurgical department of Xiangya Hospital. Neurological examination findings were unremarkable. MRI showed isointensity without significant enhancement on T1- and T2-weighted images. The lesion exhibited clearly defined borders on the sagittal, coronal, and axial images. The preliminary diagnosis was hypo- thalamic hamartoma (HH); however, the lesion was surgically removed, and histopathological examination confirmed the diagnosis of a DNET. Hypothalamic DNETs are extremely rare. Based on their clinical manifestation and imaging, DNETs are easily misdiagnosed as HHs. Diagnoses apart from HHs must be entertained when a hypothalamic lesion is being investigated. https://thejns.org/doi/abs/10.3171/2020.2.PEDS19764 KEYWORDS dysembryoplastic neuroepithelial tumor; seizure; hypothalamus; epilepsy YSEMBRYOPLASTIC neuroepithelial tumors (DNETs) lasted approximately 5 minutes and typically included con- are benign, glioneuronal neoplasms that are in- vulsions, eye turning, frothing at the mouth, facial cyano- cluded in the group of neuronal and mixed neu- sis, and limb stiffness, and they were alleviated spontane- Dronal-glial tumors.1 DNETs often manifest as medically ously. This seizure type occurred only twice. The second intractable epilepsy, and they primarily occur in children form was more common in this child; it lasted only a few and adolescents. Since the first report by Daumas-Duport seconds and was marked by uncontrolled laughter, but no et al. in 1988,2 the rate of accurately diagnosed DNETs in loss of consciousness. Although the patient had used ox- patients with seizures has increased due to developments carbazepine for a number of years (beginning at a dose of in pathology and imaging. DNETs most often occur in the 100 mg/day and gradually increasing to 450 mg/day), the temporal lobe, followed by other supratentorial cortical lo- seizures were not well controlled. Findings on neurologi- cations, including the frontal, parietal, and occipital lobes.3 cal examination were unremarkable. Her hormone func- DNETs have also been reported in the cerebellum, brain- tion was assessed, but no obvious abnormity was observed. stem, and thalamus.4,5 In this report, we present the case of a hypothalamic DNET. Examination The seizures were recorded twice by video electro- Case Report encephalography (EEG) and lasted 30–40 seconds. The events included sudden and involuntary laughter accompa- Presentation nied by slight rigidity and spasming of her limbs. Initially, A 5-year-old girl presented with a 4.6-year history of the EEG showed wide low voltage. Subsequently, spike seizures. Her seizures had two main forms and would be- waves and slow waves appeared in the full set of leads. gin without obvious inducement. Seizures of the first form The spike waves decreased, and the amplitude of the slow ABBREVIATIONS DNET = dysembryoplastic neuroepithelial tumor; EEG = electroencephalography; HH = hypothalamic hamartoma. SUBMITTED December 21, 2019. ACCEPTED February 4, 2020. INCLUDE WHEN CITING Published online April 10, 2020; DOI: 10.3171/2020.2.PEDS19764. 34 J Neurosurg Pediatr Volume 26 • July 2020 ©AANS 2020, except where prohibited by US copyright law Unauthenticated | Downloaded 10/01/21 01:21 AM UTC Cai et al. FIG. 1. The lesion is marked by the white arrow. Axial CT scan (A) showing a circular lesion without calcification in the left area of the suprasellar cistern. MR images showing a lesion in the hypothalamus that is isointense on T1-weighted (B) and T2-weighted (C) sequences. The lesion has no significant enhancement on the axial (D), sagittal (E), and coronal (F) images after gadolinium injection. waves progressively increased. The frequency of slow tochemical staining demonstrated the following findings: waves lessened gradually. The seizure ceased when the negative p53 and isocitrate dehydrogenase 1 expression frequency reached 1–2 Hz. and positive glial fibrillary acidic protein, oligodendrocyte A noncontrast cerebral CT scan showed a circular le- transcription factor 2, NeuN, and O6-methylguanine-DNA sion (32 Hounsfield units) about 4 mm in diameter in the methyltransferase expression. left area of the suprasellar cistern. The lesion showed no calcification (Fig. 1). MRI showed a lesion in the hypothal- Discussion amus that had isointensity without significant enhance- ment on T1-weighted, T2-weighted, and FLAIR images. DNETs are benign tumors that belong to neuronal and The lesion had clearly defined borders on the sagittal, cor- mixed neuronal-glial tumors. The tumors typically mani- onal, and axial views (Fig. 1). A hypothalamic hamartoma fest as medically intractable, partial complex seizures in (HH) was the preliminary diagnosis. children and adolescents.6 Consistent with the characteris- tics of DNETs, our patient was a 5-year-old child who pre- Operation and Follow-Up sented with a 4.6-year history of seizures without known The lesion was exposed via pterional approach. A gray precipitating events. DNETs typically occur within the tumor with dimensions of 1 × 0.8 × 0.8 cm could be seen. supratentorial cortex and most commonly in the tempo- The lesion had clearly defined borders and abundant vas- ral lobe.3 On MRI, DNETs are characterized by a multi- cularity. Subtotal resection was performed using a micro- nodular structure, rendering a bubbly appearance. Mass surgical technique because the posterior portion of the effect and perilesional edema are usually absent even in lesion had close adhesion to the pedunculus cerebri and voluminous lesions.7 A triangular pattern distribution and hypothalamus. The patient had an uneventful postoper- a FLAIR rim are typical imaging findings that can be ative recovery. Over the 12-month follow-up period, the observed in cases of DNETs.8 In the current case, MRI patient was neurologically intact and seizure free (Fig. 2). on FLAIR and contrast enhancement imaging had an The results from the histopathological examination con- isointense signal, and the patient presented with gelastic firmed that the lesion was a hypothalamic DNET (Fig. 3). seizures, together rendering the mass diagnostically indis- The histopathology showed isolated neurons with large tinguishable from an HH. HHs are masses that consist of nuclei characteristically floating within the mucoid sub- well-differentiated ectopic neurons interspersed with glial stance, encircled by a glial component, which was com- cells, and they are located in the tuber cinereum of the posed mainly of oligodendroglia-like cells. Immunohis- hypothalamus.9 They are congenital malformations rather J Neurosurg Pediatr Volume 26 • July 2020 35 Unauthenticated | Downloaded 10/01/21 01:21 AM UTC Cai et al. FIG. 2. The lesion location is marked by the white arrow on axial (A), sagittal (B), and coronal (C) images. As the 12-month follow- up MRI examination shows, most of the tumor tissues have been removed. than cancerous tumors. Prototypical clinical presentations zures, who had multifocal involvement of diverse sites in of HHs include precocious puberty and gelastic seizures the central nervous system, including the temporal lobe, that begin in infancy.10 The signal intensity of HH lesions third ventricle, and basal ganglia, as well as partial involve- on MRI is hypointense on T1-weighted sequences and hy- ment of the hypothalamus. The patient did not undergo ag- perintense on T2-weighted sequences.11 Therefore, based gressive therapy and died of acute myocardial infarction.18 on age, clinical manifestations, and imaging, the preop- A DNET simply located in the hypothalamus has not been erative diagnosis was HH. Only after performing histo- reported yet. pathological examination was the diagnosis of a DNET Our patient was initially diagnosed with an HH. She confirmed. DNETs have intracortical nodules within a presented with medically intractable epilepsy without microcystic, vacuolated background. The structure ad- precocious puberty. Thus, we did not consider continuing ditionally contains columnar architecture of uniform oli- antiepileptic medication treatment or using gonadotropin- godendrocyte-like cells, which are lined around variously releasing hormone agonists. Resection, endoscopic resec- shaped and sized microcysts. This morphology is called tion, laser ablation, and Gamma Knife radiosurgery were “specific glioneuronal elements,” which, accompanied by viable options. Due to the long medical history and poor numerous interspersed floating neurons, is the most dis- family finances, her parents were eager for a cure to her tinctive pathological feature of DNETs.12 However, not all illness in an expeditious and economic way. Thus, we de- DNETs have specific glioneuronal elements, and some cided to perform resection. However, we need to point out DNETs exhibit a growth pattern similar to that of diffuse that if