a 67-year - old male presented to the emergency eye centre ( eec ) complaining of a painful right eye of 5-day duration .
clinical examination revealed a visual acuity ( va ) of 6/9 with minimal conjunctival injection , anterior chamber ( ac ) cells 1 + and posterior synechiae ( ps ) .
a diagnosis of anterior uveitis was made and the patient was commenced on topical prednisolone 1% and topical cyclopentolate 1% .
the response to this treatment was good and the steroids were slowly tapered over 1 month ; however , before cessation of treatment , the anterior segment inflammation worsened .
the patient represented with va 6/36 and ac cells 3 + , extensive ps and a posterior vitritis .
2 , the topical treatment was increased and an urgent referral was made to the uveitis service . at review ,
4 weeks after presentation , the anterior and posterior segment inflammation remained and a white mass was noted in the peripheral nasal retina [ fig . 1 upper plate ] , almost at the ora serrata .
a diagnosis of presumed toxoplasma chorioretinitis was made and treatment with pyrimethamine and sulfadiazine followed by oral clindamycin was initiated . on further questioning , it was discovered that there was the possibility of a previous pulmonary tuberculosis ( tb ) infection .
he had had no previous treatment for active tuberculosis . in view of concern over possible reactivation of tb with an increase in oral steroids ,
quantiferon and induced sputum sampling were also performed ( all negative ) and the dose of prednisolone was increased to 60 mg daily .
blood cultures were also negative and there was no serological evidence of toxoplasma infection ( toxoplasma latex < 16 ) .
( upper plate ) 10 mhz b - scan ultrasonography of subretinal mass ( nasal peripheral retina - white arrow ) ( middle plate ) hematoxylin and eosin stained section of the retinal biopsy showing brown fungal hyphae ( black arrows ) coursing through the abscess.(lower plate ) masson fontana stain showing a positive melanin brown reaction .
thin arrows showing fungal septae and thick arrows indicate dichotomous branching of hyphae the patient responded to oral steroids and clindamycin , with a reduction in intraocular inflammation and improved va of 6/18 after 2 weeks treatment .
however , when the oral prednisolone was gradually reduced and the clindamycin stopped ( after 5 weeks treatment ) , there was an increase in intraocular inflammation and va reduced to 3/60 .
a diagnostic pars plana vitrectomy was therefore performed with vitreous sampling , which revealed a chronic vitritis without infectious agent or neoplasia .
no herpes family viruses or toxoplasma organisms were identified on polymerase chain reaction testing . in order to clinch the diagnosis , combined cataract surgery , retinal biopsy , and intraocular oil tamponade was performed .
the nasal sub - retinal mass was biopsied using a 23-gauge ( 23 g ) vitrector hand piece and samples sent to histopathology and microbiology .
close inspection showed brown pigmented septate branching hyphae that stained strongly with masson fontana melanin stain and with a periodic acid schiff ( pas ) and silver stain [ fig .
the presence of a melanin containing , septate , branching , and mycelial fungus on histopathology was diagnostic of phaeohyphomycosis infection , on morphology alone .
prolonged fungal culture of the biopsy was negative and 18s ribosomal subunit polymerase chain reaction ( pcr ) was also negative ( most likely due to the presence of pcr inhibitors in the sample ) .
the absence of a culture and pcr result did not permit precise speciation of the phaeohyphomycosis fungus .
the patient remained under joint care and was treated with antifungal therapy for 6 months ; however , no primary source of fungal infection was identified . following retinal biopsy
the patient developed a retinal fold secondary to proliferative vitreoretinopathy ( pvr ) , which extended from the biopsy site to the optic disc .
vitrectomy , removal of silicone oil , epiretinal membrane peel , subretinal pvr removal and retinectomy were performed with laser retinopexy and intraocular gas tamponade .
unfortunately , the patient required two further operations for rhegmatogenous retinal detachment . currently , the retina is flat with heavy silicone oil tamponade and the va is 2/60 .
further retinal biopsy taken during vitrectomy for retinal detachment revealed no fungal elements on microscopy and intravitreal amphotericin b was also injected perioperatively .
phaeohyphomycosis is a collective term that describes infection caused by darkly pigmented mycelial fungi , a feature secondary to the presence of melanin within their cell walls .
the most common phaeohyphomycosis genera pathogenic to humans include exophilia , phialophora , wangiella , bipolaris , exserohilum , cladophialophora .
morphology by histopathology is sufficient to make a diagnosis of phaehyphomycosis , characterized by branching , septate hyphae with confirmation of melanin by tinctorial staining ( masson fontana or an equivalent ) .
whilst histopathology permits a clear diagnosis of phaeohyphomycosis , the precise species does require pcr and cultures .
infection is presumed to be as a result of implantation following superficial trauma and exposure to contaminated soils or organic matter .
systemic infections result either from direct invasion from a more superficial site , such as the paranasal sinuses or by means of haematogenous dissemination .
the central nervous system is most frequently affected but other sites including lung , bone , and joint or peritoneum may also be involved .
, primary cerebral phaeohyphomycosis seems to ignore this rationale with more than half of cases being fully immunocompetent .
melanin within the cell walls of dematiaceous fungi may provide the reasons for this disparity ; it has been extensively investigated as a virulence factor .
however , this is the first time a subretinal abscess caused by phaeohyphomycosis has been documented in the medical literature .
the most plausible theory involves a haematogenous route ( metastatic infection ) transmission from a peripheral nidus to the subretinal space , which in turn initiated a posterior and anterior segment uveitis .
patients with underlying lung disease appear to be at a increased risk of pulmonary phaeohyphomycosis .
it is possible that , in this patient , the lung parenchyma may have been a source of infection , in the setting of chronic , low level immune suppression / modulation by the methotrexate therapy with reactivation of a previous self - limiting respiratory phaeomycotic infection , with subsequent dissemination .
posterior segment pathology is usually diagnosed by characteristic clinical signs , extensive systemic investigations and non - invasive ocular investigations such as fluorescein angiography .
however , it is not uncommon for vitreoretinal surgeons to aid in the diagnosis of a posterior uveitis of unknown aetiology by sampling vitreous , retina or choroidal tissue , leading to increased diagnostic accuracy and prompt treatment .
reported 13 cases of retinochoroidal biopsy in unclear uveitis seven of the cases tissue biopsy helped direct specific treatment .
intraocular lymphoma , recurrence of lymphoblastic leukaemia , chronic scleritis , toxoplasmosis , and metastasis were diagnoses confirmed as a result of the tissue biopsies performed .
malignancy was also excluded in several cases , which allowed for a trial of medications such as oral steroids and anticytomegalovirus agents . in this case , it is difficult to postulate whether the final va and outcome have been improved by surgical intervention .
it is clear that the patients intraocular inflammation was increasing rapidly and only high dose steroids subdued the response . without sub - retinal biopsy ,
the specific treatment of this patient 's phaeohyphomycosis with antifungal medication would not have been possible and years of treatment for idiopathic uveitis may have ensued .
 a 67-year - old former gold miner with rheumatoid arthritis , treated with steroids and methotrexate , presented to eye casualty with a painful right eye . 
 examination revealed an anterior uveitis and despite an initial response to topical steroids , the intraocular inflammation worsened with anterior and posterior uveitis development . 
 re - examination showed a white mass in the peripheral nasal retina initially suspected of being active toxoplasmosis infection and anti - toxoplasmosis treatment commenced . 
 after improvement and tapering of this treatment , the intraocular inflammation reoccurred . 
 cytopathological examination of a pars plana vitrectomy obtained vitreous sample that showed a non - diagnostic non - infectious chronic vitritis . 
 the vitreoretinal surgeons elected to do a direct biopsy of the white subretinal mass in the peripheral nasal area . 
 this revealed , quite unexpectedly , an abscess containing pigmented phaeohyphomycosis fungi . 
 this case report documents the multidisciplinary approach that assisted in clinching a final diagnosis and the role of sub - retinal biopsy in this unprecedented scenario . 
Case Report
Discussion