a 23-year - old indian female presented to a tertiary institute of northeast india with the chief complaints of dimness of vision , pain and redness in the right eye ( od ) for 3 months . the patient was previously treated elsewhere with two posterior sub - tenon injections of triamcinolone acetonide given 6 weeks apart . ocular alignment was normal with a visual acuity of counting finger at 3 m in the od . there was minimal sclerouveitis noted in the inferior - temporal quadrant of od . on slit - lamp examination , od showed 360 posterior synechiae with anterior chamber flare and cells ( + + + ) with 1 mm hypopyon [ fig . there was a suspected mass in the inferior - temporal quadrant behind the iris , pushing it anteriorly . ( a ) slit - lamp photograph of anterior chamber of right eye showing hypopyon with anterior chamber reaction ( flare + + + , cells + + + ) ; ( b and c ) the lesion in the ciliary body region of right eye in t2-weighted image of magnetic resonance imaging in coronal and axial planes , respectively . imaging gave the probable diagnosis of ciliary body melanoma b - scan ultrasound ( b - scan usg ) of od was suggestive of ciliary body mass with adjoining exudative retinal detachment ( erd ) . usg bio - microscopy findings were consistent with the findings of b - scan usg . the patient was advised with complete blood count with peripheral blood smear which was within normal limit . syphilis screening ( venereal disease research laboratory ) was nonreactive with normal thyroid function test and negative mantoux test ( 5tu ) reading . based on the clinical examination and baseline investigations , we came to the differential diagnosis of ciliary body melanoma or similar tumors . after obtaining informed consent , enucleation was carried out in od , and eyeball specimen was sent to ocular pathology laboratory for histopathological analysis . in grossing , there was a grayish - white - colored tumor seen in the inferior - temporal part of the ciliary body measuring ( 10.99  7.98 ) mm . adjoining the grayish - white ciliary body mass , there was an erd noted [ fig . 2 ] . gross photograph of eyeball showing grayish - white mass in the ciliary body region with gross thickening of ciliary body and adjoining exudative retinal detachment microscopic description of enucleated eyeball showed peripheral corneal vascularization . an eosinophilic mass was seen in the ciliary body with diffuse plasmacytoid cells , with reactive lymphoid follicle and other inflammatory cells [ fig . ( a ) plasmacytoid cells ( h and e , 200 ) ; ( b ) exudation in anterior chamber ( 200 ) ; ( c ) the scleral vascularization with inflammatory cells ( 400 ) ; and ( d ) the eosinophilic exudation of the adjoining exudative retinal detachment ( 200 ) ihc for both kappa and lambda was positive . ihc for igg4 was positive in occasional cells which also expressed cd138 ( plasma cells ) . nearly , 30% of all the cd138 positive plasma cells were found to be igg4-positive [ fig . 4 ] . please note that the immunoglobulin g4 positivity was around 30% of total cd-138 plasma cells positivity . negative control slide did not show immunostaining protein chemistry revealed hypergammaglobulinemia with higher levels of total protein and gamma fraction . a hematologist was consulted , and bone marrow examination revealed mild anemia , for which she was given supportive treatment . in the postoperative period , on follow - up at 6 weeks , she was given prosthesis in od , and the patient was doing well till her last review . protein chemistry revealed hypergammaglobulinemia with higher total protein ( 8.5 g / dl ; normal 6.48.2 g / dl ) and gamma fraction ( 2.06 g / dl ; normal 0.911.71 g / dl ) . igg4-rd is a systemic condition characterized by tissue igg4-positive lymphoplasmacytic infiltrative lesions in the body with high serum level of igg4 . it was initially found that mikulicz 's disease was related with igg4-rd and later established that this condition can occur in any of the ocular adnexal tissue . the median age of patients with igg4-rd was 59 years ( varies from 30 to 86 years ) , and almost equal preponderance was found in both sexes . igg4-rd is a recently proposed clinical entity with varied clinical features , but its pathogenesis remains to be understood clearly . after enucleation , on histopathology , plasma - lymphocytic inflammations were noted in iris and ciliary body region . on ihc , plasmacytoma was ruled out due to polyclonality in kappa and lambda light chain positivity . bone marrow examination did not show any other abnormality , consistent with the pathology discussed here . review of literature showed that igg4-rd occurs in orbit and adnexal tissue in older age group . our present understanding of ophthalmic igg4-rd having several unique characteristic is limited to orbital and adnexal tissues . to the best of our knowledge , this is the first described igg4-rd in intraocular structures mimicking as a ciliary body melanoma . this study was funded by sri kanchi sankara health and educational foundation , guwahati , india . this study was funded by sri kanchi sankara health and educational foundation , guwahati , india .