eumycetoma is a chronic , relentlessly progressive , granulomatous subcutaneous disease caused by a true fungus .
it commonly occurs in the extremities , the foot being the most common site of involvement .
cranial involvement has only rarely been reported[24 ] and is often due to direct extension from the paranasal sinuses .
recently , characteristic mri findings of the  dot - in - circle  sign and a conglomeration of multiple extremely hypointense  dots  have been reported in pedal eumycetoma.[58 ] we describe these characteristic findings on an mri of the brain in a case of cranial eumycetoma ( ce ) that was caused by direct inoculation of the organism madurella grisea .
a 35-year - old man presented with complaints of seizures for 1 year , slowly increasing left parietal swelling for 6 months , and sudden - onset weakness of the right upper and lower limbs and inability to speak for 6 days .
he had been diagnosed elsewhere as cranial tuberculosis on the basis of imaging findings and had been on regular antituberculous treatment and steroids for the last 1 year .
there was no significant premorbid illness apart from history of trauma to the scalp on the left side . on examination ,
the patient had a glasgow coma scale ( gcs ) score of 10/15 , papilledema , and right facial palsy .
there was a small , tender , focal scalp swelling in the left parietal region .
mri of the brain done elsewhere 1 year ago showed a left parasagittal , homogeneously enhancing , dural - based mass with surrounding edema , involving the underlying cerebral cortex .
ct scan [ figure 1 ] done in our institution at the time of presentation showed an intensely enhancing mass , with features of osteomyelitis in the adjacent parietal bone .
contrast enhanced ct scan of the brain shows an intensely enhancing mass ( arrow ) in the left frontal lobe with adjacent edema the patient underwent biopsy of the lesion via a left parietal flap .
it was firm and yellowish , with multiple blackish granules within ; it was also stuck to the calvarium .
histology [ figure 2 ] revealed fibrocollagenous connective tissue containing multiple microabscesses , with the central cavitary spaces containing several pigmented grains composed of hyphal mats .
the abscess walls displayed granulomatous reaction , with dense infiltrates of histiocytes , foreign body 
photomicrograph shows a microabscess containing pigmented grains ( arrows ) surrounded by an inflammatory reaction , including foreign body giant cells ( h and e , 90 ) postoperatively , there was some improvement in speech and right upper and lower limb power .
repeat mri after 1 year [ figures 3 and 4 ] revealed an iso- to hypointense mass and surrounding edema in the left frontal region on t2w and fluid - attenuated inversion recovery ( flair ) images .
dots  representing fungal grains and the  dot - in - circle  sign was present . when compared to the previous imaging findings , there was a slight decrease in the size of the mass and the surrounding edema . currently , he is doing well clinically .
his epilepsy is mostly controlled and he has grade 3 - 4 power in the limbs .
axial flair ( a ) and t2w ( b ) mri images show a conglomeration of multiple extremely hypointense dots ( arrows ) within an iso- to hypointense mass in the left parasagittal frontal lobe , involving the motor cortex coronal t2w mri image ( a ) shows an iso- to hypointense left parasagittal frontal lobe mass ( black arrow ) , with altered marrow signal ( white arrow ) in the overlying parietal bone .
magnified coronal t2w mri images ( b , c ) show a few hypointense dots ( open arrows ) within the hyperintense granulomas ( white stars ) separated by hypointense walls ( white arrows ) , giving the  dot - in - circle  sign
. diffusion - weighted mri image ( d ) shows small hyperintense areas ( arrow ) of restricted diffusion , probably representing microabscesses .
the recently described characteristic  dot - in - circle  mri sign in pedal eumycetoma represents a t2-hyperintense granuloma , with central hypointense 
dots  of fungal grains separated by hypointense fibrous walls.[58 ] a conglomeration of multiple hypointense dots of fungal grains against the background of inflammatory granulomas was also seen .
the grains were identified as hypointense dots on both t1w and t2w images and their mri signal was attributed to the magnetic - susceptibility effects of the paramagnetic elements of the grains .
the present case also showed the typical conglomeration of multiple extremely hypointense dots within the mass , correlating histopathologically with multiple fungal grains .
a few of the hypointense dots within the hyperintense granuloma were seen separated by hypointense walls , giving rise to the characteristic  dot - in - circle  sign on t2w images and probably correlating histopathologically with central fungal grains surrounded by dense granulomatous inflammation and fibrocollagenous tissue .
we also noted a few small areas of restricted diffusion on dwi , probably reflecting microabscesses [ figure 4d ] .
an isointense to hypointense mass on t1w and t2w images , with or without peripheral extremely hypointense areas and central necrosis , has been described in ce .
ce may be mistaken for other dural - based masses , such as meningioma or tuberculomas , even in endemic regions .
both meningiomas and tuberculomas can present with a similar iso- to hypointense dural - based mass on t1w and t2w images , but the characteristic mri findings of ce would not be present .
culture of the organism is considered the gold standard for confirming the diagnosis of eumycetoma .
however , this takes a long time and false positive results can occur due to contamination of the sample .
the characteristic mri findings can help make an early noninvasive diagnosis of ce and allow differentiation from other dural - based hypointense lesions .
 cranial eumycetoma ( ce ) due to direct inoculation of madurella grisea into the scalp is extremely rare . 
 we describe a case of ce caused by direct inoculation of m. grisea with the characteristic mri findings of the  dot - in - circle  sign and a conglomeration of multiple , extremely hypointense  dots .  
Introduction
Case Report
Discussion