The Many Faces of Myxopapillary Ependymomas

SUMMARY:

Myxopapillary ependymomas (MPEs), classified as grade 2 tumors by the World Health Organization, are rare spinal neoplasms. Despite their slow growth and generally benign nature, MPEs have a high recurrence rate and potential for CSF dissemination. This study aims to identify the MRI characteristics and pathologic patterns of MPE and investigate potential correlations between the MRI characteristics and specific histopathologic patterns. We assessed 13 patients (7 men; mean age, 45.1 years) with pathologically proved MPE. MR 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 histopathologic 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 nonenhancing MPE was noted. Large tumors exhibited a microcystic pathology pattern, with 2 cases with this pattern showing drop metastasis on MRI. Smaller tumors typically presented a solid pathology pattern with homogeneous 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.