Clinicopathological features of myxopapillary ependymoma.

Myxopapillary ependymoma (MPE) is a rare and distinct variant of ependymoma with a tendency for local recurrence and metastasis. Its clinicopathological spectrum is heterogenous, underscoring the need to understand and characterize MPE for better diagnosis and treatment. The purpose of this study was to explore the tumor biology and assess the management of patients with MPE. Tumors from a cohort of 19 patients were analyzed by light microscopy, electron microscopy, immunohistochemistry and fluorescence in situ hybridization (FISH). Clinical characteristics, therapeutic options and clinical follow-up data were also analyzed. Back pain was the most common presenting symptom. The main pathological morphology observed was papillae embedded in a myxoid background, but other rare morphologies were also present. Immunostaining revealed epidermal growth factor receptor (EGFR) expression in four MPE, while FISH for EGFR was negative. No correlation between tumor recurrence and EGFR overexpression was found. Ultrastructural examination revealed adherens junctions and intracytoplasmic lumina with microvilli. Patients with gross-total resection (GTR) had no tumor recurrence (p=0.021). Also, patients with subtotal resection (STR) followed by radiotherapy showed a higher local control rate than patients with STR alone (p=0.043). The diagnosis of MPE should be made considering the histology, immunohistochemistry, imaging studies and anatomical site. GTR of the tumor or STR followed by radiotherapy are more likely to avoid tumor recurrence than STR alone. Based on our findings, there is no correlation between tumor recurrence and EGFR expression.