[Intraocular involvement in Erdheim-Chester disease--first report in the literature: case report].

Erdheim-Chester disease (ECD) is a granulomatous and infiltrative disorder of unknown etiology with proliferation of cholesterol-containing histiocytes and peculiar bone involvement. It is very similar to Langerhans cell histiocytosis (LCH) on histology but with a different immunohistochemical profile. This is the first report of intraocular involvement in this disease. MPSG, a 46 y.o. woman, presented with proptosis of the OD. She referred ulcerated lesions on the hard palate, symmetrical and bilateral osteosclerosis of the fibulae and tibiae and a nodule in the right breast (biopsy: xantomatous histiocytic infiltrate CD68+, S-100 and CD1a negative on immunohistochemistry compatible with ECD). MRI studies demonstrated an extraconal tumor in the juxta-bulbar temporal portion of the right orbit close to the lacrimal gland and hyperintense on T1. Vision was 20/20 OU, with numerous drusen in the posterior pole, similar to basal laminar drusen. Two regions of orange subretinal infiltrates that showed progressive staining on the angiogram were seen in the peripapillary region and also close to the fovea in the OD. Choroidal neovascular membranes were seen 2 years later in OU leading to severe visual loss in the OS and to a slight visual field loss in the OD, which retained 20/20 vision. This pioneer report depicts in vivo characteristics of histiocytic granulomas in ECD. Caution should be taken with patients with ECD as potentially blinding intraocular complications may arise.