Trichobezoars develop over a number of years as hair, which is indigestible, is swallowed and then becomes matted, slowly growing into a ball. No one in our medical team, of some 30 years' experience, had seen anything like it before. It is very rare. Kev's comments Bezoars are balls of indigestable matter that gradually build up in the stomach over a number of years. Trichobezoars are perhaps the most common type of bezoar to develop, although this is a rare condition.
Trichobezoars develop in people who eat their hair, a condition called trichophagia.
Trichophagia is generally regarded as a personality disorder similar to finger nail biting. In turn, trichophagia is often linked to habitual hair plucking which is called trichotillomania . Trichobezoars are composed of hair, usually plucked from the individual's own scalp. The ingested hair always turns black, regardless of the original color, due to denaturation of proteins by the highly acidic stomach gastric juice. When a trichobezoar is removed in surgery it smells rather foul because the hair mesh traps undigested dietary fat and bacteria colonize the bezoar.