a 39-year - old male presented with decreased vision in his left eye for two days . visual acuity was 20 / 20 in the right eye and hand movement in the left eye . on slit lamp examination of the left eye , severe inflammation was seen in the anterior chamber ( cells + 4 ) and the vitreous ( cells + 4 ) . fundus examination of the left eye demonstrated thick , white , confluent sheathing surrounding the retinal veins and arteries from the posterior pole to the periphery with extensive retinal hemorrhages , optic disc swelling , and macular edema ( fig . b - scan ultrasonography and spectral - domain optical coherence tomography of the left eye showed a severely edematous and detached retina in posterior pole ( fig . fluorescein angiography demonstrated a prolonged arteriovenous transit time , blockage of fluorescein corresponding to extensive retinal hemorrhage , widespread area of capillary non - perfusion , and extensive staining of sheathing veessels ( fig . a diagnosis of occlusive retinal vasculitis resembling acute fba was made and systemic evaluation for retinal vasculitis was performed . the patient had a history of recurrent genital and oral ulcers over two years , but no other systemic manifestations of behet 's disease on presentation . the results of laboratory examinations , including serology for herpes virus , varicella zoster virus , and human immunodeficiency virus were normal or negative . other examinations , including brain magnetic resonance imaging and polymerase chain reaction assay for varicella zoster virus and cytomegalovirus in the aqueous humor , were negative or normal . however , during two weeks after treatment , the vascular sheathing and vitreous opacity gradually disappeared . systemic steroids were slowly tapered during the next two months and cyclosporine 150 mg / day was added . two months later , follow - up angiographic findings revealed a widespread area of non - perfusion in three retinal quadrants with neovascularization of the disc ( fig although panretinal photocoagulation for non - perfusion areas was performed , neovascularization progressed by four months ( fig . six months after his presentation , he developed two ulcers on oral mucosa and pseudofolliculitis on his face , along the hairline . a diagnosis of behet 's disease was made using the international criteria following a rheumatology consultation . eight months later , follow - up optical coherence tomography imaging revealed atrophy and disruption of the photoreceptor layer in the macular area ( fig . fba can be idiopathic or associated with various ocular and systemic disorders . in 1997 , kleiner   classified the patients who had the appearance of fba into three subgroups . first are patients with lymphoma or leukemia whose disease is due to infiltration with malignant cells ( frosted branch - like appearance ) . second is the group of patients who have associated viral infections or autoimmune disease ( secondary fba ) . cases associated with behet 's disease such as this study can be classified into this subgroup . finally , there is a group of otherwise healthy young patients who develop acute visual loss ( acute idiopathic fba ) . our case can be classified into acute idiopathic fba because systemic examination revealed no obvious abnormalities except positive hla - b51 and ocular findings on presentation . however , the history of recurrent oral and genital ulcers over a period of two years and a positive hla - b51 suggested the possibility of an underlying behet 's disease . obliterative retinal vasculitis and hypopyon iritis on presentation also supports ocular manifestations of behet 's disease . six months after his ocular presentation , he developed oral ulcers and pseudofolliculitis , which led the authors confirm the diagnosis of behet 's disease with secondary fba . the patient had severe occlusive vasculitis involving three quadrants of his retina , initial visual acuity was hand movement , and the patient had no visual improvement even with the proper treatment . for these reasons , the authors started early immunosuppressive treatment to prevent involvement of the contralateral eye before confirming the diagnosis of behet 's disease . the authors found six cases in pubmed using the search parameters of " frosted branch angiitis , behet 's disease . " including this study , seven cases are discussed here [ 5 - 10 ] . table 1 shows the characteristics of patients diagnosed as having secondary fba associated with behet 's disease . all cases aside from this study presented with improvement of visual acuity during the follow - up period , and three cases recovered their sight up to 20 / 20 or 10 / 10 . four cases presented with bilateral involvement , and while three cases presented with bilateral involvement initially , the other one was reported to affect both eyes , two years apart [ 5,8 - 10 ] . this case suggests that the subsequent involvement of the other eye could occur and early immunosuppressive treatment should be considered , especially in cases of initially unilateral involvement . three cases presented with neuro - behet 's disease and two cases revealed typical hypopyon iritis . all patients had a history of recurrent oral or genital ulceration , and five of six cases had a positive hla - b51 . these findings suggest that both a careful history and a positive hla - b51 can help make a diagnosis of underlying behet 's disease . in summary , this case revealed that fba can be an ocular manifestation of behet 's disease , which could initially be unilateral and result in blindness , particularly when combined with severe occlusive retinal vasculitis . this condition may consecutively involve both eyes and result in the deterioration of bilateral visual function . thus , the authors recommend that behet 's disease should be considered in a diagnostic workup for unilateral fba , and a careful history and a positive hla - b51 are helpful to establish an early diagnosis . in addition , it is recommended that patients with unilateral fba with suspicion of behet 's disease should be treated with the early immunosuppressive treatment in order to prevent the involvement of the contralateral eye .
we report an unusual case of unilateral frosted branch angiitis associated with behet 's disease , including a review of previously reported cases . a 39-year - old male with history of recurrent oral and genital ulcers presented with visual loss in his left eye . 
 fundus findings demonstrated occlusive retinal vasculitis resembling acute frosted branch angiitis . 
 laboratory examinations including viral markers revealed no abnormal findings except positive hla - b51 . 
 the patient was treated with systemic steroid and cyclosporine . 
 six months after presentation , new oral ulcers and pseudofolliculitis appeared , and he was diagnosed with behet 's disease following rheumatology consultation . during follow - up , there was no change in visual acuity of hand movement , and disc neovascularization developed even after complete panretinal photocoagulation . 
 ocular manifestations of behet 's disease can present as unilateral frosted branch angiitis , and may consecutively involve in both eyes . 
 early immunosuppressive treatment is recommended .