A cholesterol-containing foreign body granuloma presenting as an inter-metatarsal bursa.

A 68-year-old man presented with progressive forefoot swelling which coincided with the onset of type 2 diabetes mellitus. Imaging revealed a cystic inter-metatarsal mass containing two foreign bodies, which had been present for many years. Following aspiration of the mass, cholesterol crystals were observed on polarised microscopy. It is postulated that the development of diabetes triggered the shedding of cholesterol crystals around a long-standing quiescent foreign body granuloma.