Melanin distribution in a patient with bilateral diffuse uveal melanocytic proliferation utilizing wide-field polarization diversity optical coherence tomography.

Purpose: To describe novel imaging findings of bilateral diffuse uveal melanocytic proliferation (BDUMP) using wide-field polarization diversity optical coherence tomography (PD-OCT) and to explore its potential role in assessing melanin distribution and choroidal involvement Observations: Bilateral diffuse uveal melanocytic proliferation is a rare paraneoplastic syndrome that leads to progressive bilateral vision loss and characteristic ocular findings. We describe a 61-year-old woman with stage IV B ovarian clear cell carcinoma who presented with bilateral visual blurring and was diagnosed with BDUMP. Clinical features included hypopigmented patches at the level of the retinal pigment epithelium (RPE), multifocal choroidal melanocytic lesions, and exudative retinal detachment. Structural optical coherence tomography (OCT) showed serous retinal detachment, thickened RPE with skip areas of loss, neurosensory outer retinal degeneration, and a widened choriocapillaris band. In this case, wide-field PD-OCT was employed in BDUMP, revealing melanin signal within thickened RPE and choroidal melanocytic lesions, alternating with areas of signal loss corresponding to hypopigmented patches. A widened choriocapillaris band was also observed, a structural finding that warrants further investigation. Conclusions and importance: This case highlights novel imaging features of BDUMP and demonstrates the value of PD-OCT in characterizing melanin alterations and choroidal involvement