Brain infections that mimic malignancy

There exists a wide spectrum of non-neoplastic conditions which can mimic a brain tumor, both clinically and radiologically. Central nervous system (CNS) infections are the commonest conditions in this group. CNS infections presenting as space-occupying lesions (SOLs) are not uncommon, especially in developing countries with large populations in the low socio-economic groups. The infective organisms gain entry into the CNS via hematogenous dissemination, seed the parenchyma, cause tissue destruction, expansion and a host tissue response, which all contribute to the formation of SOLs, akin to neoplasms. Enhancing lesions with perilesional edema and mass effect on neuroimaging is a characteristic feature of neoplasms. Similar findings have been observed in non-neoplastic conditions, especially CNS infections. Unless there is a suspicion of infection, these lesions will be missed and treatment delayed with resultant morbidity and mortality. This review discusses the common infectious lesions that mimic CNS malignancy.