tuberculosis ( tb ) is common disease in developing and developed countries caused by various strains of mycobacteria , usually mycobacterium tuberculosis ( m. tuberculosis)14 ) . the most common initial infection site is the lung , but the brain can be infected by hematogenous transmission . tb meningitis and tuberculoma are the two most common forms of tb of the central nervous system . surgical treatment is only recommended when medical therapy fails , decompression is necessary , or the diagnosis is uncertain9,15 ) . transient worsening , appearance of new symptoms , or radiological manifestations of tb can develop after initiating of anti - tb medication4 ) . these paradoxical responses are not uncommon in human immunodeficiency virus - negative patients and have been observed in 6 - 30% of patients with a tb infection6,7 ) . these episodes of paradoxical deterioration are commonly associated with extrapulmonary tb and the central nervous system is the most common location for this presentation . however the lesion revealed indistinguishable radiological findings of a malignant intracranial tumor such as a high grade glioma after anti - tb treatment . we describe the radiological findings of the paradoxical response of a cerebral tuberculoma mimicking a malignant brain tumor . she underwent a chest computed tomography ( ct ) , which showed minimal cardiac fluid collection with pleural effusion but without pleural enhancement or thickening . the pleural fluid was an exudate , with a white blood cell count of 907/mm and 30% lymphocytes . the quantiferon tb and immunoglobulin m for the ebstein - barr virus capsid antigen was positive . she refused anti - tb medication , and her symptoms improved after aspirin and steroid treatment . brain magnetic resonance images ( mri ) showed 18 mm and 6 mm sized lesions on the pons and occipital lobe , respectively . the lesions were hypointense on t1-weighted images , and iso - intense with a central hyper - signal on t2-weighted images associated with perilesional edema and rim - enhancement after contrast administration ( fig . the diffusion images showed diffusion restriction in the central area but no increased cerebral blood volume on mr perfusion images ( fig . a follow - up chest ct showed randomly distributed miliary nodules and mixed small centrilobular nodules , suggesting pulmonary tb with miliary dissemination . anti - tb medication was started with isoniazid , rifampicin , ethambutol , and pyridoxine . at the 1 month follow - up , the thickened , peripherally enhanced lesions were enlarged and associated with aggravated perilesional edema ( fig . h mr spectroscopy revealed increased choline , lactate and lipid peak , and reduced n - acetyl aspartate and creatine , suggesting a high grade glioma rather than tuberculoma ( fig . 2 ) , and pcr for tb was positive . her medication was changed to isoniazid , rifampicin and ethambutol . after 13 months of medication , the right hemiparesis improved and the lesion had decreased in size with decreased perilesional edema ( fig . she continued the anti - tb medication to treat the remaining lung and brain lesions . involvement of the central nervous system ( cns ) is the most severe form of tb11 ) . a ring - enhancing lesion can be seen in intracranial infections or tumors such as tuberculomas , neurocysticercosis , bacterial cerebral abscesses , neurosarcoidosis , cerebral metastases , glioblastomas , and cns lymphomas8 ) . a caseating tuberculoma with a solid center shows ring and central heterogeneous enhancement and is iso- to hypointense on t1- and t2-weighted mri . a caseating lesion with a liquid center shows ring enhancement and is hypointense on t1- and hyperintense on t2-weighted mri . intense focal gyral enhancement can be seen , and a secondary cerebral infarction from obliterative end arteritis can be associated with intracranial tb16 ) . a tuberculoma with liquid necrosis shows restricted diffusion with a low apparent diffusion coefficient , whereas those with solid necrosis do not . h mr spectroscopy of the lesion reveals lipid with increased choline and reduced n - acetyl aspartate and creatine12 ) . mr perfusion also shows increased cerebral blood volume on initial images , which gradually normalize with treatment , suggesting healing of the lesion12 ) . the diagnosis is established based on the pathology results of a biopsy or detecting m. tuberculosis dna in a pcr study2 ) . treatment of a tuberculoma is based on anti - tb treatment regimens , which include two important antibiotic agents10 ) . isoniazid and rifampicin can be used for several months with combinations of other agents due to bacteria resistance . the initial treatment of extrapulmonary tb includes these two agents and the brain is not an exception . expansion of an intracerebral tuberculoma or newly detected lesions can be seen on follow up images after anti - tb medication , which is called a paradoxical response or paradoxical progression5,17 ) . the tuberculomas increase in size at 1 - 7 months after starting chemotherapy . the explanation for this paradoxical response during therapy remains unclear , but it may be related with local tissue reactivity17 ) . the brain is known as ' immunologically privileged ' , meaning that immune reactivity in brain is selective and modified . foreign antigens including pathogens deposited in the brain parenchyma are not detected efficiently by the immune system in the cns . the experimental data showed that peripheral immune sensitization can result in the immune - mediated delayed - type hypersensitivity response , which can be used to explain ' paradoxical reaction ' of intracranial tuberculoma3 ) . once the active tb is under control with chemotherapy , enhanced delayed type hypersensitivity can cause activation and accumulation of lymphocytes and macrophages at the site of bacillary deposition or toxin production1 ) . therefore , many factors may combine to produce the paradoxical response , which might be related to a host immune response , virulence of the tubercle bacilli , the infection site , antigen load , or the effects of chemotherapy . these aggravated lesions can be misdiagnosed as treatment failure or other tumorous pathology . in our case , after 1 month of treatment , our patient developed worsening symptoms , radiological aggravation with tumoral spectrum on h mr spectroscopy , and increased blood volume on mr perfusion . these findings mimicked a high grade glioma even if this center of the lesion with liquid necrosis showed a diffusion restriction . initial improvement followed by deterioration despite adequate diagnosis and treatment is strong evidence to suspect the paradoxical response on clinical grounds . the response can be effectively managed by continuing the anti - tb drugs , and eventual clinical improvement is observed in almost all reported cases . systemic corticosteroids are probably indicated to manage symptoms and cerebral edema for most patients with a cerebral paradoxical response . however , careful consideration of corticosteroid administration must be given due to possible complicating factors such as the host 's immune status or the presence of concomitant infections . surgical intervention should be considered for patients with increased intracranial pressure or an uncertain diagnosis . brain tuberculoma could be aggravated mimicking brain malignancy during administration of anti - tb medication . this paradoxical response can be effectively managed by continuing the anti - tb drugs with careful radiologic follow - up .
we report a case of a paradoxical response of a tuberculoma in the brain mimicking a brain tumor . a 76-year - old woman presented with a 2 week history of headache , dysarthia , and orthopnea . 
 brain magnetic resonance images ( mri ) revealed two rim - enhancing lesions on the pons and occipital lobe , and chest computed tomography showed randomly distributed miliary nodules . 
 the tentative diagnosis was tuberculosis ( tb ) of the brain and lung . 
 she complained of right hemiparesis and worsening general weakness after taking the anti - tb medication . on the monthly follow - up images , 
 the enhanced lesions were enlarged with increased perfusion and choline / creatinine ratio , suggesting a high grade glioma . 
 a surgical resection was completed to diagnose the occipital lesion , and the tuberculoma was pathologically confirmed by a positive tb - polymerase chain reaction . 
 the anti - tb medication was continued for 13 months . 
 a follow - up mri showed decreased size of the brain lesions associated with perilesional edema , and the clinical symptoms had improved . 
 brain tuberculoma could be aggravated mimicking brain malignancy during administration of anti - tb medication . 
 this paradoxical response can be effectively managed by continuing the anti - tb drugs .