Rosai–Dorfman disease presenting as choroidal melanoma: a case report and review of the literature

Abstract

Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is a rare non-malignant proliferation of histiocytes of unknown aetiology. It was first recognised as a distinct clinicopathologic entity in 1969, and is classified as an idiopathic non-Langerhans cell histiocytosis. The disease process is usually self-limiting and often involves lymph nodes, but extranodal involvement is well-described and any anatomic site can be involved. We describe a unique case of a 40-year-old male who presented with a fundus mass diagnosed clinically as choroidal melanoma. The tumour showed rapid growth. The patient developed a total retinal detachment and underwent enucleation. The globe contained a choroidal tumour with histologic and immunophenotypic features characteristic of RDD. The literature of ocular Rosai-Dorfman disease was reviewed. This is the first case in the English literature of intraocular choroidal RDD, mimicking choroidal melanoma. Rosai-Dorfman disease can present as a mass-producing lesion in the choroid and may mimic other choroidal tumours. The case emphasises the need to consider diagnostic biopsy prior to definitive treatment of choroidal tumours.