Eschbacher, Kathryn L.

Myxopapillary ependymomas (MPEs) have an indolent clinical course, corresponding to World Health Organization Grade I. A total of 13 pediatric MPEs have been reported in the literature with “anaplastic features,” including elevated proliferative activity (≥5 mitoses/10 high-power fields), necrosis, and microvascular proliferation. No consensus exists regarding the prognostic significance of such features. A retrospective clinicopathologic review of pediatric MPEs diagnosed between 1996 and 2018 at Mayo Clinic was performed. Totally, 8 pediatric MPEs (6 male; age: 7.52 to 16.88 y) were identified. Totally, 3 had disseminated disease at presentation. All patients underwent surgical resection (7 gross total; 1 subtotal). Totally, 5 cases harbored ≥5 mitoses/10 high-power fields (range: 5 to 9), 3 of which showed necrosis (2 with disseminated disease). Postsurgery, 2 patients received radiation; one with disseminated disease and another with increased mitotic activity/necrosis; neither has recurred (follow-up: 1.18 and 3.19 y). In all, 2 patients with disseminated disease, elevated mitotic activity, and necrosis had new metastatic disease/progression of nonresected metastatic foci (2.6 and 26.8 mo), received radiation therapy, and remain progression free (3.01 and 9.34 y). All patients are alive (median follow-up 1.31 y, range: 0.66 to 11.75). Among pediatric MPEs, the concurrent presence of elevated mitotic activity and necrosis may be associated with an aggressive clinical course, warranting closer surveillance and consideration of adjuvant therapies.

PURPOSE: Myxopapillary ependymomas (MPE) have an indolent clinical course, corresponding to WHO Grade I designation. 13 pediatric MPEs have been reported in the literature to show “anaplastic features”, including elevated proliferative activity (≥5 mitoses per 10 high-power fields and/or Ki67 labeling index of >10%), necrosis, and microvascular proliferation. No consensus exists regarding the prognostic significance of such features. PROCEDURE: Retrospective clinicopathologic review of pediatric MPEs diagnosed between 1996-2018 at Mayo Clinic. RESULTS: The study included 8 pediatric MPEs (6 male; age range 7.52-16.88 years). 3 had disseminated disease at presentation. All patients underwent surgical resection (7 gross-total; 1 subtotal). 5 cases harbored ≥5 mitoses per 10 high-powered fields (range: 5-9), 3 of which showed necrosis (2 with disseminated disease). Following surgery, 2 patients received radiation; one with widely disseminated disease and another with increased mitotic activity and necrosis; neither has recurred at last follow-up (1.18 and 3.19 years). 2 patients with disseminated disease, elevated mitotic activity, and necrosis had new metastatic disease/progression of non-resected metastatic foci (2.6 and 26.8 months). Both received radiation therapy and have remained progression free (3.01 and 9.34 years). All patients are alive (median follow-up 1.31 years, range: 0.66-11.75 years). CONCLUSION: Our findings suggest that among pediatric MPEs, the concurrent presence of elevated mitotic activity and necrosis may be associated with a more aggressive clinical course, warranting closer surveillance and consideration of adjuvant therapies such as radiation. Attention to the presence of mitotic activity and necrosis may help identify children at higher risk for tumor recurrence/progression.

AimsCalcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare entity that can occur anywhere within the central nervous system. Histologically, CAPNON has been characterised as a benign, calcified, fibro‐osseous lesion with a characteristic chondromyxoid fibrillary matrix with dense calcification and varying degrees of spindle, epithelioid, fibrous, meningothelial and giant cells. The underlying aetiology of CAPNON is controversial and incompletely understood. The aim of this study was to perform a comprehensive radiological and histological review to further characterise this entity.Methods and resultsIn this article, we review our institutional 20‐year experience including 37 cases of CAPNON with detailed pathological analysis, evaluation of concurrent lesions, correlation with radiological imaging, and critical review of the literature. The classic histological finding of chondromyxoid matrix was present in one‐third of cases. Underlying or dual pathologies were frequent, and included diverse underlying conditions. Radiologically, dense calcification and dural attachment were the most common features. Enhancement was often low, but was more prominent in the setting of inflammatory changes, aggressive growth, and dual pathology.ConclusionOur results suggest that CAPNON represents a spectrum of reactive processes that can arise in association with diverse underlying pathologies, including inflammatory, degenerative, vascular and neoplastic lesions.