The many faces of myxopapillary ependynomas.

Abstract

Myxopapillary ependymomas (MPE), classified as grade 2 tumors by the WHO, are rare spinal neoplasms. Despite their slow growth and generally benign nature, MPE have a high recurrence rate and potential for cerebrospinal fluid dissemination. This study aims to identify the MRI characteristics and pathological patterns of MPE and investigate potential correlations between the MRI characteristics and specific histopathological patterns. We assessed 13 patients (7 men; mean age, 45.1 years) with pathologically proven MPE. MRI images were reviewed for tumor location, size, T1 and T2 signal characteristics, contrast enhancement, hemosiderin cap presence, vertebral scalloping, drop metastasis, and prominent intradural flow voids. Four histopathological patterns (microcystic, solid, hemorrhagic, and high hyalin content) were defined and segmented, with surface areas measured and percentages calculated relative to the total tissue surface. Most tumors were in the lumbar region (84.61%), with MRI revealing typical features such as T2 hyperintensity (100%) and contrast enhancement (92.3%). A rare non-enhancing MPE was noted. Large tumors exhibited a microcystic pathology pattern, with two cases with this pattern showing drop metastasis on MRI. Smaller tumors typically presented a solid pathology pattern with homogenous MRI signals. This study underscores the diverse MRI presentations of MPE and suggests a potential link between microcystic patterns in pathology and large MPE with drop metastasis.ABBREVIATIONS: MPE= myxopapillary ependymoma.