fungal infections are infrequent causes of central nervous system ( cns ) ring enhancing lesions in patients with advanced acquired immune deficiency syndrome ( aids ) . more frequent processes include toxoplasmosis , primary cns lymphoma , metastases , pyogenic brain abscesses , and tuberculomas ( in areas of high endemicity for tuberculosis ) . the radiologic finding of a ring enhancing lesion is insufficient to distinguish between the possible etiologic causes . toxoplasmic encephalitis , the most common infectious cause in those with aids in the united states , is usually diagnosed retrospectively following a therapeutic challenge . the number and location of lesions , in conjunction with serologic testing , may suggest an alternate non toxoplasma - related cause and indicate a need for early brain biopsy . we herein present a reported case of fonsecaea monophora causing a brain abscess in a patient with aids . a 54-year - old caucasian female with hiv / aids ( cd4 42 cells / mm and undetectable viral load ) presented to the emergency department in february 2012 ( day 0 ) with complaints of intermittent headache , vomiting , and episodes of left arm twitching for the preceding week ( day 7 ) . these episodes were becoming more frequent and longer in duration , lasting up to 15  min at a time . the patient was diagnosed with aids in may 2011 ( day 270 ) with a cd4 count of 20 cells / mm and viral load of 142,098 copies / ml . she was started on antiretroviral therapy ( art ) with atazanavir 300  mg , ritonavir 100  mg , and a fixed dose combination of tenofovir- emtricitabine 300/200  mg orally daily in june 2011 ( day 256 ) . at that time , prophylaxis was initiated with trimethoprim - sulfamethoxazole ( tmp - smx ) 160/800  mg orally daily and azithromycin 1200  mg orally weekly for pneumocystis jirovecii and mycobacterium avium complex , respectively . she reported good adherence to her medication regimen at follow up clinic visits and was noted to have an undetectable viral load 2 months after initiation of art ( day 200 ) . other significant past medical history included hepatitis c without cirrhosis and late latent syphilis treated with 3 weekly intramuscular injections of benzathine penicillin g in april  may 2011 ( completed on day 280 ) . she had a history of intravenous ( iv ) drug abuse but denied use in the last 20 years . she was a smoker ( 20-pack years ) and had been making efforts to quit alcohol ( cut back from 24 to 3 beers per day ) . on examination , her temperature was 36.6  c , heart rate 82 beats / minute , blood pressure 94/56 mm of hg , and respiratory rate 16 breaths per minute . she had 2/5 muscle strength in all muscle groups of her left arm and diminished deep tendon reflexes in that extremity . babinski and hoffman signs were not present , and the rest of her exam was unremarkable . initial laboratory testing revealed a leukocyte count of 3.110 cells / mm ( normal 4.0  10.010 cells / mm ) , hemoglobin of 12.7  g / dl ( normal 11.5  15.5  g / dl ) , platelet count of 11510/mm ( normal 150  40010/mm ) , and creatinine of 0.96  mg / dl ( normal 0.50  1.04  mg / dl ) . a non - contrasted computed tomography scan on day 0 revealed a right parietal lobe lesion . the lesion was better characterized on magnetic resonance imaging of the brain with contrast , which revealed a 2  cm ring enhancing lesion with surrounding vasogenic edema ( fig . she was initiated on levetiracetam 500  mg orally twice daily and empiric therapy for toxoplasmosis with the following regimen : pyrimethamine 200  mg oral loading dose followed by 50  mg orally daily , sulfadiazine 1  g orally 4 times a day , and leucovorin 20  mg orally daily . additional laboratory data became available on day + 1 : toxoplasma gondii igg and serum cryptococcal antigen were negative . considering her progressive symptoms , nonreactive toxoplasma serology , and claimed adherence to tmp - smx prophylaxis , she underwent right parietal craniotomy with resection of the mass for pathologic examination and culture on day + 7 . she was started on dexamethasone 4  mg orally every 6  h in the postoperative period . final pathology results available on day + 8 confirmed the presence of a dematiaceous fungus in a background of granulomas with langhans giant cells , and central necrosis ( fig . she was started on voriconazole with two 360  mg iv loading doses 12  h apart followed by 240  mg every 12  h and liposomal amphotericin b 300  mg iv daily while awaiting identification of the fungal pathogen . her protease inhibitor based art was altered to emtricitabine - tenofovir 200/300  mg and efavirenz 300  mg orally daily to avoid drug interactions with voriconazole . in the ensuing days she was able to participate with physical therapy but had residual left arm weakness . on day + 12 , voriconazole was changed to 400  mg oral twice daily . a dexamethasone taper was initiated , however on day + 16 she was noted to have worsening confusion . corticosteroids were increased to dexamethasone 4  mg iv every 6  h. her mental status worsened further on day + 18 to the point where she could not maintain her airway . based on her previously expressed wishes , she was placed on comfort measures and died . the isolate was sent to associated regional university pathologists ( arup ) for identification based on sequencing of the internal transcribed spaced region . antifungal minimum inhibitory concentrations ( mic ) were as follows : amphotericin b 2  g / ml ; itraconazole 0.5  g / ml ; voriconazole 0.06  g / ml ; and posaconazole 0.25  g / ml . these results became available after the patient had passed away . our patient had several features that tilted the balance in favor of an early biopsy . thirdly , she had a solitary lesion , which is very unusual for toxoplasmosis , and differentiation from all the other possible etiologies requires tissue diagnosis . exserohilum was involved in a recent multistate outbreak related to contaminated drugs from a single pharmacy . many fungi , which were previously identified as separate genera , have been retrospectively reclassified on the basis of genetic analysis . genetic analysis is also helpful in differentiating between closely related species , as in this case . however , based on what has been reported in the literature , f. pedrosoi primarily causes cutaneous forms of chromoblastomycosis , whereas f. monophora appears to be neurotropic . there have only been 6 previously reported cases in the literature of brain involvement by f. monophora . additional information about antifungal susceptibility ( when reported ) can be found in table 2 . with advances in molecular methods of identification , genus and species reclassification has at times been performed retrospectively after initial publication , as in the cases reported by lucasse   and nobrega , respectively . it is difficult to assess how many previous reports regarding closely - related fungi are truly germane to f. monophora . treatment guidelines have not been firmly established , owing to the small number of cases , but it seems that surgical excision in conjunction with antifungal therapy offers the best chance of cure . , it has excellent cns penetration , achieving high concentrations in both the brain parenchyma and cerebrospinal fluid . recently , a study in mice found posaconazole to be superior to amphotericin b and itraconazole for disseminated f. monophora 
 . our patient had been adherent with her art regimen as evidenced by two instances of a suppressed viral load three months apart . the dramatic drop in viral load suggests the possibility of immune reconstitution inflammatory syndrome ( iris ) , which can lead to apparent worsening of pre - existing opportunistic infections . iris has been known to present several months after initiation of art   and should be part of the differential diagnosis . our patient clinically worsened on day 16 after admission . at that time , she was on day 8 of appropriately - dosed voriconazole therapy . we hypothesize that her initial apparent response to therapy may have been related to steroids , and subsequent worsening correlated temporally with initiation of steroid taper . in conclusion , a solitary ring enhancing lesion in a patient with hiv / aids should lower the threshold for pursuing a tissue diagnosis early in the course of illness . use of the newer azoles in combination with surgical therapy seems to be the most effective treatment .
fungal infections are infrequent causes of brain abscesses . 
 fonsecaea monophora is a dematiaceous fungus that appears to be neurotropic . 
 we report a case of fonsecaea monophora infection in a patient with acquired immunodeficiency syndrome , and review previous reports of brain abscesses by this organism .