BACKGROUND Cerebrotendinous xanthomatosis is a rare, autosomal recessive, inherited lipid storage disease characterized by accumulation of cholestanol and cholesterol in most tissues. The disease is caused by mutations in the sterol 27-hydroxylase gene, leading to a block in bile synthesis, with accumulation of substrates for this enzyme, including cholesterol, resulting in an increase in the conversion of cholesterol to cholestanol. METHODS A 26-year-old woman presented with gradually increasing bilateral ankle swelling. She had a history of bilateral cataracts and left-sided hemiparesis. She had mental retardation, with a history of delayed milestone development. Her serum cholesterol levels were elevated. Aspiration of both ankle swellings revealed histiocytes and many foreign body giant cells. There were numerous rectangular to rhomboid crystals in the background. CONCLUSIONS Very few articles are available on the cytologic features of tendinous xanthomas; hence we tried to highlight these features.