Tumor-Like Lesions of the Brain in MRI and CT-scan

"nIntroduction: The objective of this paper is to demonstrate a variety of non-neoplastic pathologies that may present with a mass effect and/or abnormal enhancement, thus simulating neoplasia. "nMaterials and Methods: We collected 77 cases of various tumor mimics from teaching files of three institutions. All patients presented with intra- and/or extra–axial lesions and imaging findings that could, potentially, mimic brain neoplasia. "nResults: Assessment of central nervous system pathology may be very challenging. The usual description of mass effect and abnormal enhancement, typical of brain neoplasia, can also be shared by a variety of non-neoplastic etiologies. Radiologists should be familiar with these tumor mimics, and shold be included as differential diagnoses. We categorized and these non-neoplastic lesions, which could potentially mimic extra-and/or intra- axial brain tumors, into the following groups: "n1) Normal variant (giant (tumefactive) perivascular spaces) "n2) Infection (tuberculosis, cysticercosis, and fungal lesions) "n3) Syndromes (NF1, Rosai-Dorfman Syndrome, Lhermitte-Duclos, Krabbe Disease (adult type). "n4) Vascular lesions (vascular malformations, aneurysms and cerebral venous sinus thrombosis) "n5) Autoimmune and inflammatory processes (MS, ADEM, encephalitis, sarcoidosis and PML) "n6) Idiopathic (idiopathic hypertrophic pachymeningitis) "n7) Congenital brain lesions (cortical dysgenesis and heterotopias) "n8) Miscellaneous (postictal brain lesions) "nConclusion: In this paper, we present a large collection of non-neoplastic tumor mimics. Awareness, understanding, and recognition of these mimics may permit the radiologist to play a significant role in the prevention of unwanted surgical interventions or extensive diagnostic evaluation procedures.