Bucillamine-induced gigantomastia with galactorrhea and hyperprolactinaemia

Gigantomastia is characterised by excessive breast growth and can occur as a rare, drug-induced adverse event. D-penicillamine is the most frequent cause of drug-induced gigantomastia. Only one case of gigantomastia due to bucillamine, an analogue of D-penicillamine, has been reported so far. We herein report a case of bucillamine-induced gigantomastia presenting with acute enlargement of the bilateral breasts and accessory breast tissue in the axillae 7 months after the start of bucillamine therapy. Awareness about this rare adverse event is important since bucillamine is still widely used in Japan and Korea.