What are the shared MRI characteristics and clinical associations of spinal cord astrocytomas and ependymomas?

Both spinal cord astrocytomas and ependymomas appear as expansile intramedullary lesions with low T1 and high T2 signal intensity and can show variable contrast enhancement. They are associated with an increased incidence in patients with neurofibromatosis type 1 (astrocytomas) and type 2 (ependymomas). Key diagnostic features include the presence of a central location and hemorrhagic components more common in ependymomas. A common pitfall is mistaking these tumors for demyelinating lesions, which typically lack mass effect and enhancement.