PURPOSE: To depict the well-known and atypical magnetic resonance imaging (MRI) findings of non-neoplastic central nervous system (CNS) complications of extra- CNS tumors and portray additional information from advanced techniques, such as diffusion and perfusion MRI. MATERIALS AND METHODS: MRI scans of 92 patients were retrospectively evaluated based on the non-neoplastic effects induced by treatment or the remote effects of the tumor itself. Patients with brain metastases and/or patients who had whole brain radiation therapy were excluded so as not to take the primary radiation effects into consideration. RESULTS: Sixteen patients (9 females and 7 males; age range, 11-68 years; median age, 45 years) had positive findings other than brain metastases. Six patients had posterior reversible encephalopathies, 3 patients had chemotherapy toxicity to the white matter, and 2 patients had acute strokes involving the posterior fossa and bilateral anterior circulation territory. Three patients had bilateral radionecrosis of the temporal lobe due to radiotherapy given for the vicinal tumor (nasopharyngeal carcinoma). One patient had encephalitis in the bitemporal region and one patient had cerebellar degeneration, each of whom had a paraneoplastic syndrome. CONCLUSION: One of the major and noteworthy complications of malignancies directly affecting survival is brain metastasis, but non-neoplastic complications are infrequently encountered and are thus underestimated, either due to the absence of a true diagnosis or the lack of information pertaining to the clinical outcome. It is important for the radiologist to recognize these effects so as to help the clinician develop an optimal treatment strategy and avoid irreversible complications.
PURPOSE: To depict the well-known and atypical magnetic resonance imaging (MRI) findings of non-neoplastic central nervous system (CNS) complications of extra- CNS tumors and portray additional information from advanced techniques, such as diffusion and perfusion MRI. MATERIALS AND METHODS: MRI scans of 92 patients were retrospectively evaluated based on the non-neoplastic effects induced by treatment or the remote effects of the tumor itself. Patients with brain metastases and/or patients who had whole brain radiation therapy were excluded so as not to take the primary radiation effects into consideration. RESULTS: Sixteen patients (9 females and 7 males; age range, 11-68 years; median age, 45 years) had positive findings other than brain metastases. Six patients had posterior reversible encephalopathies, 3 patients had chemotherapy toxicity to the white matter, and 2 patients had acute strokes involving the posterior fossa and bilateral anterior circulation territory. Three patients had bilateral radionecrosis of the temporal lobe due to radiotherapy given for the vicinal tumor (nasopharyngeal carcinoma). One patient had encephalitis in the bitemporal region and one patient had cerebellar degeneration, each of whom had a paraneoplastic syndrome. CONCLUSION: One of the major and noteworthy complications of malignancies directly affecting survival is brain metastasis, but non-neoplastic complications are infrequently encountered and are thus underestimated, either due to the absence of a true diagnosis or the lack of information pertaining to the clinical outcome. It is important for the radiologist to recognize these effects so as to help the clinician develop an optimal treatment strategy and avoid irreversible complications.