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Thomas L. Beaumont, Jakub Godzik, Sonika Dahiya and Matthew D. Smyth

The authors report the case of a 14-year-old male with a subependymal giant cell astrocytoma (SEGA) that occurred in the absence of tuberous sclerosis complex (TSC). The patient presented with progressive headache and the sudden onset of nausea and vomiting. Neuroimaging revealed an enhancing left ventricular mass located in the region of the foramen of Monro with significant mass effect and midline shift. The lesion had radiographic characteristics of SEGA; however, the diagnosis remained unclear given the absence of clinical features of TSC. The patient underwent gross-total resection of the tumor with resolution of his symptoms. Although tumor histology was consistent with SEGA, genetic analysis of both germline and tumor DNA revealed no TSC1/2 mutations. Similarly, a comprehensive clinical evaluation failed to reveal any clinical features characteristic of TSC. Few cases of SEGA without clinical or genetic evidence of TSC have been reported. The histogenesis, genetics, and clinical approach to this rare lesion are briefly reviewed.

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Acalvaria

Case report

Ammar H. Hawasli, Thomas L. Beaumont, Timothy W. Vogel, Albert S. Woo and Jeffrey R. Leonard

Acalvaria is a rare congenital malformation characterized by an absence of skin and skull. The authors describe a newborn at an estimated 38 weeks gestational age who was delivered via cesarean section from a 32-year-old mother. Upon delivery, the child was noted to have a frontal encephalocele and an absence of calvaria including skull and skin overlying the brain. A thin membrane representing dura mater was overlying the cortical tissue. After multiple craniofacial operations, including repair of the encephalocele and application of cultured keratinocytes over the rostral defect, the patient demonstrated significant closure of the calvarial defect and was alive at an age of more than 17 months with near-average development.

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Thomas L. Beaumont, David D. Limbrick Jr., Keith M. Rich, Franz J. Wippold II and Ralph G. Dacey Jr.

OBJECTIVE

Colloid cysts are rare, histologically benign lesions that may result in obstructive hydrocephalus and death. Understanding the natural history of colloid cysts has been challenging given their low incidence and the small number of cases in most reported series. This has complicated efforts to establish reliable prognostic factors and surgical indications, particularly for asymptomatic patients with incidental lesions. Risk factors for obstructive hydrocephalus in the setting of colloid cysts remain poorly defined, and there are no grading scales on which to develop standard management strategies.

METHODS

The authors performed a single-center retrospective review of all cases of colloid cysts of the third ventricle treated over nearly 2 decades at Washington University. Univariate analysis was used to identify clinical, imaging, and anatomical factors associated with 2 outcome variables: symptomatic clinical status and presentation with obstructive hydrocephalus. A risk-prediction model was defined using bootstrapped logistic regression. Predictive factors were then combined into a simple 5-point clinical scale referred to as the Colloid Cyst Risk Score (CCRS), and this was evaluated with receiver-operator characteristics.

RESULTS

The study included 163 colloid cysts, more than half of which were discovered incidentally. More than half of the incidental cysts (58%) were followed with surveillance neuroimaging (mean follow-up 5.1 years). Five patients with incidental cysts (8.8%) progressed and underwent resection. No patient with an incidental, asymptomatic colloid cyst experienced acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly half (46.2%) of symptomatic patients presented with hydrocephalus. Eight patients (12.3%) presented acutely, and there were 2 deaths due to obstructive hydrocephalus and herniation. The authors identified several factors that were strongly correlated with the 2 outcome variables and defined third ventricle risk zones where colloid cysts can cause obstructive hydrocephalus. No patient with a lesion outside these risk zones presented with obstructive hydrocephalus. The CCRS had significant predictive capacity for symptomatic clinical status (area under the curve [AUC] 0.917) and obstructive hydrocephalus (AUC 0.845). A CCRS ≥ 4 was significantly associated with obstructive hydrocephalus (p < 0.0001, RR 19.4).

CONCLUSIONS

Patients with incidentally discovered colloid cysts can experience both lesion enlargement and symptom progression or less commonly, contraction and symptom regression. Incidental lesions rarely cause acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly one-half of patients with symptomatic colloid cysts present with obstructive hydrocephalus, which has an associated 3.1% risk of death. The CCRS is a simple 5-point clinical tool that can be used to identify symptomatic lesions and stratify the risk of obstructive hydrocephalus. External validation of the CCRS will be necessary before objective surgical indications can be established. Surgical intervention should be considered for all patients with CCRS ≥ 4, as they represent the high-risk subgroup.

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Diane J. Aum, David H. Kim, Thomas L. Beaumont, Eric C. Leuthardt, Gavin P. Dunn and Albert H. Kim

There has been increasing awareness that glioblastoma, which may seem histopathologically similar across many tumors, actually represents a group of molecularly distinct tumors. Emerging evidence suggests that cells even within the same tumor exhibit wide-ranging molecular diversity. Parallel to the discoveries of molecular heterogeneity among tumors and their individual cells, intense investigation of the cellular biology of glioblastoma has revealed that not all cancer cells within a given tumor behave the same. The identification of a subpopulation of brain tumor cells termed “glioblastoma cancer stem cells” or “tumor-initiating cells” has implications for the management of glioblastoma. This focused review will therefore summarize emerging concepts on the molecular and cellular heterogeneity of glioblastoma and emphasize that we should begin to consider each individual glioblastoma to be an ensemble of molecularly distinct subclones that reflect a spectrum of dynamic cell states.