Bilateral Diffuse Uveal Melanocytic Proliferation in a Patient with Chronic Myelomonocytic Leukemia: A Rare Case and Literature Review.

Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a rare paraneoplastic syndrome characterized by bilateral uveal melanocyte proliferation and progressive visual disturbance. While most commonly associated with solid tumors, its occurrence in hematologic malignancies is exceedingly rare. We report a case of BDUMP in a 64-year-old male recently diagnosed with chronic myelomonocytic leukemia (CMML), who presented with subacute, painless bilateral blurred vision. Multimodal imaging revealed suggestive features of BDUMP, including orange-red subretinal patches, retinal pigment epithelium mottling, and diffuse choroidal thickening, consistent with early structural involvement despite preserved central vision. No intraocular mass or signs of inflammation were observed. The patient did not receive specific treatment for BDUMP, and visual acuity remained stable during follow-up. This case underscores the importance of considering BDUMP in the differential diagnosis of bilateral visual symptoms in patients with hematologic malignancies. Although rare, BDUMP may occur in the context of CMML. Recognition through multimodal imaging and interdisciplinary collaboration is essential, and further research is needed to clarify its pathogenesis and improve management strategies.