A Dandy-Walker Malformation Associated with Ganglioglioma
The Dandy-Walker malformation (DWM) is a rare congenital malformation involving the posterior fossa. It is characterized by a triad of neuroimaging findings: complete or partial agenesis of the cerebellar vermis, cystic dilatation of the fourth ventricle, and an enlarged posterior fossa. The condition was first described by Dandy and Blackfan in 1914 and is the most common congenital malformation of the cerebellum, with an incidence of about one in 25,000 to 30,000 live births. The diagnosis of DWM is primarily based on these characteristic imaging findings, which can be observed on computed tomography (CT) and magnetic resonance imaging (MRI). The malformation is often associated with other congenital anomalies and cytogenetic abnormalities, but the co-existence of DWM with neoplasms is exceedingly rare. This case report presents a rare instance of DWM associated with ganglioglioma, a low-grade central nervous system (CNS) tumor.
The patient in this case was a 6-year-old boy who presented with a 3-month history of headache. He did not report dizziness, nausea, vomiting, or limb weakness. His vision, muscular strength, and muscular tone were all normal. Laboratory examinations revealed several abnormalities, including an elevated C-reactive protein level (21.7 mg/L), increased blood glucose (7.6 mmol/L), and decreased levels of albumin (39.6 g/L), blood potassium (3.5 mmol/L), sodium (136.5 mmol/L), and phosphorus (1.4 mmol/L). Cerebrospinal fluid (CSF) cytology was unremarkable. Imaging studies, including CT and MRI, revealed findings consistent with a variant form of DWM. Additionally, a round soft tissue mass was observed above the sellar region, with uneven internal density. The upper part of the lesion extended to the interphalangeal cistern, and the boundary near the right parahippocampal gyrus was not clearly demarcated.
The patient underwent a puncture of the hypothalamus, and tissue samples were sent for pathological examination. Histopathological analysis revealed the presence of ganglioglioma, a tumor composed of proliferated glial cells, mature and immature ganglion cells, and vascular proliferation. Immunohistochemical staining showed that the tumor cells were positive for glial fibrillary acidic protein (GFAP), Olig-2, neuronal nuclear antigen (NeuN), and CD34. However, the tumor cells were negative for mutations in the v-raf murine sarcoma viral oncogenes homolog B1 (BRAF) V600E, p53, isocitrate dehydrogenase 1 (IDH1) R132H, and Histone H3.3/H3.1 in the codon for lysine 27 (H3K27M). Based on these radiological and pathological findings, the patient was diagnosed with DWM associated with ganglioglioma, classified as World Health Organization (WHO) grade I.
The neurosurgeons recommended close observation rather than further tumor resection or adjuvant therapy. Six months later, follow-up CT and MRI scans showed no significant changes in the lesion, and the patient’s headache symptoms were successfully alleviated. This case highlights the rare association between DWM and ganglioglioma and suggests a potential link in the pathogenesis of these two conditions that warrants further investigation.
The etiology of DWM remains largely unknown, although it is occasionally familial. The most widely accepted theory involves a developmental arrest of the hindbrain before the third month of gestation. Several genetic mutations have been implicated in the pathogenesis of DWM, including those in the sonic hedgehog (Shh) signaling pathway genes, zinc finger protein 1 (ZIC1) and ZIC4, and fibroblast growth factor genes (FGF) 8 and FGF17. In this case, no pathological molecular alterations, including BRAF V600E, were identified through next-generation sequencing.
DWM is often associated with other congenital anomalies and can present with a variety of clinical manifestations. Approximately 70% to 90% of patients with DWM develop supratentorial hydrocephalus, which is the most common complication of this malformation. Other associated conditions include nephroblastoma, tongue hamartoma, and intracranial cavernous angioma. However, the incidence of DWM associated with CNS gliomas has not been reported, making this case particularly noteworthy.
The differential diagnosis of DWM includes other posterior fossa abnormalities such as Joubert syndrome, mega cisterna magna (MCM), Blake pouch cyst, isolated vermian hypoplasia, arachnoid cyst, and cerebellar hypoplasia. Accurate diagnosis is crucial for appropriate management and prognosis. Treatment options for DWM include shunt placement (ventriculoperitoneal, cystoperitoneal, or combined), membrane excision, and endoscopic procedures. Cystoperitoneal shunts are currently favored by many neurosurgeons. The prognosis for patients with DWM varies widely; some individuals may remain asymptomatic throughout their lives, while others may experience severe complications or even death, particularly when associated with other syndromes.
In this case, the patient’s ganglioglioma was managed conservatively, with close observation and regular follow-up. The decision to avoid further surgical intervention was based on the tumor’s low-grade nature and the absence of significant progression over time. This approach underscores the importance of individualized treatment plans tailored to the specific characteristics of each case.
The co-existence of DWM and ganglioglioma in this patient raises intriguing questions about the potential shared mechanisms underlying these conditions. Although the exact relationship remains unclear, the identification of such associations provides valuable insights that could guide future research. Understanding the molecular and genetic basis of these conditions may lead to the development of novel therapeutic strategies and improve patient outcomes.
In conclusion, this case report presents a rare instance of DWM associated with ganglioglioma, highlighting the importance of comprehensive diagnostic evaluation and individualized management. The findings underscore the need for further research to elucidate the underlying mechanisms linking these conditions and to optimize treatment approaches for affected patients.
doi.org/10.1097/CM9.0000000000000457
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