What is the differential diagnosis for a supratentorial mass in a child that appears partially cystic and partially solid on MRI?

The differential diagnosis includes pilocytic astrocytoma, which often presents with a cystic component and an enhancing mural nodule. Primitive neuroectodermal tumors (PNETs) are also considered, typically appearing as heterogeneous masses with possible calcifications. Hemorrhagic lesions can mimic these tumors, so careful evaluation of signal characteristics on T1 and T2-weighted images is crucial. Always consider ganglioglioma and dysembryoplastic neuroepithelial tumor (DNET) as potential mimickers, especially if the lesion is cortical-based.