Editor,—Juvenile xanthogranuloma (JXG) is a rare disorder of infants and very young children affecting the ocular structures, particularly the iris.

It is characterised by spontaneous hyphaema associated with a yellowish, poorly demarcated iris tumour and increased intraocular pressure; the aetiology is unknown.1 The ocular lesions are usually unilateral and should be differentiated from amelanotic melanoma, iris leiomyoma, haemangioma, and other iris lesions.2-4 Early diagnosis and treatment determine the final visual outcome.

The aim of the present study was to describe the use of ultrasound biomicroscopy (UBM) to define precisely the location of the tumour before excision and to correlate the UBM findings with the histopathological pattern.