Intracranial "white" epidermoid tumours - An imaging approach and systematic review.

INTRODUCTION: Intracranial epidermoid cysts are rare congenital inclusion cysts that can be divided into the classical "black epidermoid" and the exceedingly rare "white epidermoid". White epidermoids are often misdiagnosed because they have different imaging features compared to black epidermoids. There is a paucity of imaging review on white epidermoids. We hereby derive an explanation for the variable imaging features of white epidermoids and propose an imaging approach to distinguish white epidermoids from black epidermoids. METHODS: We conducted a review of white epidermoids in PubMed and Cochrane databases based on PRISMA principles. Qualitative analysis was carried out on the selected cases of white epidermoids, focusing on pathogenesis, imaging features, treatment and prognosis. RESULTS: Out of 1281 studies, we identified 26 full-text articles, comprising 68 patients with white epidermoid cysts, including an illustrative case example from our institution. White epidermoids have completely different MRI signals compared to the classical black epidermoids. Owing to tumour adhesions to the surrounding structures, there is a higher risk of leakage of white epidermoid content during surgery, causing severe aseptic meningitis. We demonstrate an approach to explain the variable imaging features of white epidermoids based on their cyst content - white epidermoids with low T2 signals content often contain high protein levels and viscosity, while those with high T2 signals contain blood products. CONCLUSION: During preoperative planning, it is important to identify white epidermoids. Extensive neurovascular damage should be avoided during surgery given the favourable prognosis of the epidermoids regardless of the extent of tumour resection.

Motor deficits at presentation and predictors of overall survival in central nervous system lymphomas.

PURPOSE: Central nervous system lymphomas (CNSL) can present with motor and non-motor symptoms. In many central nervous system tumors, motor deficits are associated with significant morbidity and functional impairment, and correlate with worse prognosis. CNSLs however, often exhibit remarkable response to chemotherapy and radiotherapy with corresponding symptom improvement. We investigate the survival outcomes and trajectories of motor and functional recovery in a cohort of patients presenting with and without initial motor deficits. METHODS: Patients who underwent biopsy and with a histologically confirmed CNSL between 2008 and 2019 were retrospectively identified. Baseline demographic variables, comorbidities, presenting symptoms, histological type, neuroimaging features (location and number of lesions), and treatment administered (pre- and post-operative steroid use and chemotherapy regime) were recorded. Dates of death were obtained from the National Registry of Births and Deaths. Motor power and performance status at admission, 1 month and 6 months were determined. RESULTS: We identified 119 patients, of whom 34% presented with focal motor deficits. The median overall survival (OS) was 26.6 months. Those with focal motor deficits had longer OS (median 42.4 months) than those without (median 23.3 months; p = 0.047). In multivariate Cox analysis, age (HR 1.04 per year; p = 0.003), CCI (HR 1.31 per point; p < 0.001), leptomeningeal/ependymal involvement (HR 2.53; p = 0.016), thalamus involvement (HR 0.34; p = 0.019), neutrophil:lymphocyte ratio (HR 1.06 per point; p = 0.034), positive HIV status (HR 5.31; p = 0.003), preoperative steroids use (HR 0.49; p = 0.018), postoperative high-dose steroids (HR 0.26; p < 0.001) and postoperative low-dose steroids (HR 0.28; p = 0.010) were significant predictors of OS. By one month, 43% of surviving patients had full power, increasing to 61% by six months. CONCLUSION: A significant proportion of patients with initial motor deficits recovered in motor strength by six months. In our population, those presenting with motor deficits had paradoxically better overall survival.