MR Imaging of Pial Melanosis Secondary to a Posterior

Summary: A 36-year-old man presented with trouble speaking and bilateral progressive hearing loss. MR imag-ing and histopathologic results revealed a posterior fossa melanotic ependymoma. Pial surfaces appeared hyperin-tense on T1-weighted images and hypointense on T2-weighted images. Histopathologic examination revealed that tumor cells and interstitial spaces had abundant mel-anin accumulation. There was no evidence of hemosiderin in tumor cells and in interstitial spaces. Pial melanin ac-cumulation secondary to a posterior fossa melanotic ependymoma explained our MR findings. Intracytoplasmic melanin pigment has been de-scribed infrequently in primary intracranial tumors such as astrocytoma, ganglioglioma, choroid plexus papilloma and carcinoma, medulloblastoma, centra