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Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a rare paraneoplastic syndrome first described by Machemer 40 years ago in a patient with pancreatic carcinoma.1 Gass and associates later expanded the syndrome to include round red patches in the fundus, multifocal areas of retinal pigment epithelial (RPE) atrophy, rapidly progressive cataracts, retinal detachments, and choroidal thickening.2 There have been 34 reported cases since Machemer first described it, and all have had bilateral involvement.3,4,5,6,7,8 After searching databases such as MEDLINE (1947 to the present), Exerpta Medica/EMBASE (1947 to the present), and Ophthalmic Literature (1947 to 1988) using the key words BDUMP, melanocytic proliferation, paraneoplastic, and uvea, we report the first case—to the best of our knowledge—of unilateral diffuse uveal melanocytic proliferation (DUMP) found in a patient with metastatic lung cancer.
A 55 year old woman with a two year history of metastatic small cell lung carcinoma undergoing chemotherapy was referred for a decrease in vision and anterior displacement of the temporal iris. Visual acuity was 20/20 in the right eye and 20/40 in the left. Examination revealed anterior bowing of her left iris, a nuclear cataract, and multiple grey oval patches separated by a reticular pattern of yellow‐orange pigmentation in her left fundus (fig 11).). Nummular areas of RPE atrophy with pinpoint staining were revealed by fluorescein angiography, along with shallow neurosensory detachments overlying an attenuated RPE by optical coherence tomography/scanning laser ophthalmoscope (OCT/SLO) examination (fig 11).). In addition, 20 MHz B‐scan ultrasound showed diffuse unilateral choroidal thickening. High frequency (35 MHz) B‐scan ultrasound revealed an anterior uveal metastasis causing narrowing of the angle, and a small overlying exudative retinal detachment in her left eye (fig 22).). These findings were secondary to both anterior uveal small cell lung cancer and ipsilateral unilateral DUMP. Her right eye was normal. The patient returned at a 4 month follow up and did not have DUMP in the fellow eye.
There has been some controversy regarding the aetiology of RPE loss as specific antibodies—of the sort classically associated with autoimmune retinopathies such as cancer associated retinopathy (CAR) and melanoma associated retinopathy (MAR)—have not been discovered in BDUMP. Some speculate that the increased metabolic demand of hyperproliferating melanocytes leads to retinal hypoxia and the progression of cataract with RPE dysfunction.9 Others have suggested that the RPE loss is a result of a distinct paraneoplastic process independent of what leads to melanocytic proliferation.4 Histopathological specimens of BDUMP have shown benign proliferation of melanocytes within the choroid with widespread dysfunction and necrosis of the overlying RPE (even in areas with minimal melanocytic proliferation).2,10 Gass theorised that toxic or immunological factors liberated by the interaction of a systemic carcinoma with normal melanocytes of the uveal tract are responsible for this extensive degeneration.2
The uveal metastasis in our patient was in close proximity to the melanocytes of the ipsilateral affected RPE and can explain the local production of factors previously described by Gass. Clinically, one sees islands of atrophic RPE lying in a sea of “orange‐pigment” lipofuscin laden retina (fig 11).). The complete absence of any signs of diffuse uveal melanocytic proliferation in the right eye suggests that systemic factors were not responsible in our case. Though the aetiology of the RPE toxicity remains unclear, this case shows that BDUMP does not have to be bilateral. Therefore, it should be called diffuse uveal melanocytic proliferation (DUMP).
Supported by The EyeCare Foundation, Inc, New York City, NY, USA
Competing interests: None declared.