Xanthomata are non-neoplastic, reactive tumour like processes, usually arising in response to lipid profile disturbances. They represent a localised collection of tissue histiocytes containing lipid (foamy macrophages).¹ Xanthomata occur more frequently in the skin, tendons, subcutaneous tissue and gastrointestinal tract, but, unlike them, urinary bladder xanthoma (UBX) appears to be a rare condition, with only 12 cases (including our two cases) reported in the Japanese and English literature.^2–4 It is believed that xanthomata are reactive proliferations of histiocytes secondary to alterations in the lipid serum. Because xanthoma is one of the presentations of hyperlipidaemia, all patients, irrespective of the site, should be investigated for an underlying lipid disorder.¹ However, only 50% of patients with UBX have hyperlipidaemia. Xanthoma may occur in either primary hyperlipidaemia, or secondary hyperlipidaemia, such as in diabetes mellitus. Occasionally, xanthomata occur in normolipidaemic states. Interestingly, xanthomata can occur as part of many tumour or inflammatory processes, and be related to trauma or surgery, as has been hypothesised for stomach xanthoma.⁵ The latter was probably due to disturbances in lipid metabolism in …