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Aims: Methylation profiling (MP) is increasingly incorporated in the diagnostic process of central nervous system (CNS) tumours at our centres in The Netherlands and Scandinavia. We aimed to identify the benefits and challenges of MP as a support tool for CNS tumour diagnostics. Methods: About 502 CNS tumour samples were analysed using (850 k) MP. Profiles were matched with the DKFZ/Heidelberg CNS Tumour Classifier. For each case, the final pathological diagnosis was compared to the diagnosis before MP. Results: In 54.4% (273/502) of all analysed cases, the suggested methylation class (calibrated score ≥0.9) corresponded with the initial pathological diagnosis. The diagnosis of 24.5% of these cases (67/273) was more refined after incorporation of the MP result. In 9.8% of cases (49/502), the MP result led to a new diagnosis, resulting in an altered WHO grade in 71.4% of these cases (35/49). In 1% of cases (5/502), the suggested class based on MP was initially disregarded/interpreted as misleading, but in retrospect, the MP result predicted the right diagnosis for three of these cases. In six cases, the suggested class was interpreted as 'discrepant but noncontributory'. The remaining 33.7% of cases (169/502) had a calibrated score <0.9, including 7.8% (39/502) for which no class indication was given at all (calibrated score <0.3). Conclusions: MP is a powerful tool to confirm and fine‐tune the pathological diagnosis of CNS tumours, and to avoid misdiagnoses. However, it is crucial to interpret the results in the context of clinical, radiological, histopathological and other molecular information. [ABSTRACT FROM AUTHOR]

Histiocytosis is a heterogeneous group of disease entities, comprised by two main categories, namely Langerhans and non-Langerhans cell histiocytoses. Central nervous system involvement in histiocytosis is considered very rare and is often secondary to affection of anatomically related bone structures and/or multi-organ disease. We present a never-before described case of rare childhood histiocytosis with hybrid features of Langerhans cell histiocytosis and juvenile xanthogranuloma confined to the central nervous system in a 2- and a half-year-old boy with distinct treatment response to clofarabine. The case also emphasizes the diagnostic significance of stereotactic brain biopsy. [ABSTRACT FROM AUTHOR]

Rønning P, Andresen PA, Hald JK, Heimdal K, Scheie D, Schreiner T, Helseth E. Low frequency of VHL germline mutations in Norwegian patients presenting with isolated central nervous system hemangioblastomas – a population-based study. Acta Neurol Scand: 2010: 122: 124–131. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objectives – Explore the genetic and clinical incidence of von Hippel–Lindau disease in patients presenting with isolated central nervous system hemangioblastomas. Results – We report a 3.2% (1/31) and 25% (8/32) incidence of genetic and clinical VHL, respectively. One patient tested positive for a VHL mutation that has not previously been reported. This genotype phenotypically predicts VHL type 2B. We had seven patients with renal cysts. In a total follow-up of 33 person years, none of these cysts progressed to renal cell carcinoma. Conclusion – von Hippel-Lindau disease anchored in germline mutations of the VHL gene is rare in the Norwegian population as opposed to clinical VHL disease, which appears to be relatively common in patients with apparently sporadic hemangioblastomas. There exists insufficient data regarding the natural history of patients with renal cysts, which makes it difficult to include or disregard these lesions as an entity of VHL disease. [ABSTRACT FROM AUTHOR]