The correlation between the histological features and clinical outcome remains poor in pediatric intracranial ependymomas. We performed a retrospective study of a group of 31 patients (diagnosed from 1985 to 1995) to assess prognostic implications of the current grading system, of histological and immunohistochemical features, and of ploidy status estimated by flow cytometry. Immunoexpression of a broad spectrum of antigens was evaluated, including MIB-1, topoisomerase-IIalpha, cyclin D1, glial and epithelial proteins (GFAP, EMA, cytokeratins), molecules involved in controlling apoptosis (bcl-2, caspase-3/CPP32), and p53 oncoprotein. Univariate and multivariate statistical analyses were performed to evaluate the influence of each variable on both the progression free survival (PFS) and the overall survival (OS) with at least 7-year follow up. Although we showed a significant correlation between histological grade and prognosis, the current grading system failed in predicting outcome in nearly one third of individual cases. Problems with interpathologist reproducibility were also demonstrated. The extent of surgical resection was the only clinical factor that was associated with survival. Both the PFS and the OS were significantly decreased for the following pathological variables: increased cellularity (>300 nuclei per HPF), mitotic activity of >7 per 10 HPF, increased MIB-1 labeling index (LI), topoisomerase-IIalpha LI, S-phase fraction, and p53 and bcl-2 positivity. Increased cyclin D1 LI was demonstrated to have only a marginally significant impact on PFS. A flow chart modeling was further performed to formulate a scheme for discriminating of prognostic subgroups. Based on that, p53 immunopositivity and/or MIB-1 LI of >5% (after subtotal resection) or MIB-1 LI of >15% (after complete resection) were the strongest indicators of the tumor's aggressive behavior and of a poor prognosis of the disease. Foci of hypercellularity should be specifically looked for in ependymomas for assessing the immunohistochemical studies.

Our study showed that whole-body FDG-PET is an efficient and useful method for the initial staging of children with HD. FDG-PET in combination with lung CT should be recommended as a screening method prior to other conventional imaging modalities to plan a rational staging protocol. Large multicentre prospective studies are necessary to verify this conclusion.

The objective of this study was to evaluate the efficacy of 2-chlorodeoxyadenosine (2-CdA), a purine nucleoside analog, in treating recurrent Langerhans cell histiocytosis (LCH) in children. This study retrospectively analysed the clinical records of 13 patients who were seen in the department for recurrent LCH. These patients were treated consecutively with 2-CdA chemotherapy between July 1997 and May 2005. Median age at diagnosis was 4 years 7 months and median pre-treatment duration of disease was 16.4 months. Four children received 0.1 mg kg-1 per day for 7 days and nine patients 5 mg m-2 per day for 5 days, repeated every 21 days. The maximum number of courses of 2-CdA per patient was limited to six. Seventy-six courses of 2-CdA were administered without difficulty. All 13 patients (100%) had a clinical response documented by radiographic investigation. Nine patients did not require additional therapy and remain in complete remission (CR). Four remaining children are currently disease-free after receiving other therapy as irradiation (two cases) or maintenance chemotherapy (vinblastine, prednisone and 6-mercaptopurine) (one case) or chemotherapy (vinblastine) + irradiation (one child) ( Table I). Hematologic toxicity was minimal and no infectious complications were documented. Median follow-up after initiation of 2-CdA treatment was 4 years 3 months (range 7 months - 8 years 2 months). This experience confirms the reported efficacy of 2-CdA in the treatment of LCH. However, further studies are needed to determine the role of this agent in high-risk patient who did not achieve complete remission after 2-CdA administration.