Polypoidal choroidal vasculopathy as a complication of choroidal osteoma

Choroidal osteoma (CO) is a rare benign tumor that particularly affects young, healthy women. Its prognosis is influenced by complications, such as choroidal neovascularization (CNV), subretinal hemorrhage, subretinal fluid (SF), decalcification status, and overlying retinal pigment epithelium (RPE) atrophy. In case of CNV as the complication of CO, it is typically present in the classic form; however, reports on polypoidal choroidal vasculopathy (PCV) have been rare. Here, we report a case of an older, male patient with PCV as a complication of CO. Patient concerns: A 70-year-old male patient visited the hospital with vision impairment in the right eye since 2 weeks. Diagnosis: Fundus examination revealed a red-yellow, well-demarcated, scalloped lesion around the optic nerve in each eye; the lesions were highly reflective on ultrasound examination, and thus, CO was diagnosed. Indocyanine green fluorescence angiography and optical coherence tomography (OCT) revealed that the right eye also had PCV accompanied with SF. OCT confirmed the presence of large quiescent type 1 CNV bilaterally in decalcified areas of the lesions adjacent to the optic nerve. Interventions: Intravitreal bevacizumab (IB) injection was performed. Outcomes: Best-corrected visual acuity had improved and OCT showed a decrease in the SF, while OCT angiography showed partial regression of branching vascular network. Conclusion: CO can be accompanied by quiescent type 1 CNV; this should be closely monitored because it can progress to PCV. Optical coherence tomography, alongside indocyanine green fluorescence angiography, is useful for the diagnosis and monitoring of potential CNV as a complication of CO.