AIM: To explore the multimodal imaging features of choroidal osteoma.

METHODS:Retrospectively observational case series. Nine patients(15 eyes)with choroidal osteoma presented to Xi'an No.3 hospital from October 2015 to August 2019 were included in the study. Among them, there were 2 males and 7 females. All patients received the best corrected visual acuity, fundus color photography, short wavelength fundus autofluorescence(SW-AF), infrared fundus autofluorescence(IR-AF), fundus fluorescein angiography(FFA), indocyanine green angiography(ICGA), optical coherence tomography(OCT)and orbital X-ray computed tomography(CT).

RESULTS: In 15 affected eyes, lesions were involved in macula and optic disc in 5 eyes(33%), lesions were located in macula in 8 eyes(53%), peripapillar lesions in 2 eyes(13%). Choroidal osteomas presented as orange-red or yellow-white lesions with pigmentation on the surface in fundus color photographies. SW-AF images showed that choroidal osteomas presenting with mottled hypofluorescence and hyperfluorescence in 15 eyes(100%), while IR-AF images showed that all of the choroidal osteomas presenting punctate and patchy hypofluorescence and hyperfluorescence. FFA showed that 15 eyes(100%)of choroidal osteoma had gradually enhanced brightness, of which 6 eyes(40%)had severe leakage of fluorescence from sub-retinal neovascularization(SRNV). ICGA images revealed SRNV in 9 eyes(60%), all corresponding area of choroidal osteomas showed low fluorescence in the early stage of angiography, and the brightness of tumors increased during angiography gradually. OCT images showed that choroidal osteomas with inhomogeneous reflection in 10 eyes(67%); choroidal osteomas presented with hypo-reflectivity in 5 eyess(33%). All of the choroidal osteomas(100%)presented as high density bone mass on CT images.

CONCLUSION: Choroidal osteoma is orange-red or yellow-white, and expressed as bone mass on CT images, which is an important basis for diagnosis of choroidal osteoma. Damaged RPE leads to appearance of strong and weak mottled SW-AF and IR-AF in the location of choroidal osteomas. FFA and ICGA are helpful to clarify the abnormal circulation in the lesion area. The intensity of cross-sectional reflection in choroidal osteomas are different on OCT images, meanwhile, OCT was helpful to observe the condition of subretinal effusion and neovascularization.