Giant prolactinoma mimicking bone tumor.

Prolactinomas are the most common of the hormone-secreting pituitary tumours. Most of them are small in size <10 mm (microprolactinomas) and few are >10 mm (macroprolactinomas). It is well known that clinical presentations of prolactinomas are quite different between genders (4,5). The vast majority (95%) of prolactinomas in women are microadenomas which present with the clinical manifestations of hyperprolactinaemia. In contrast, men with prolactinomas often present because of symptoms due to the size of the tumour rather than impotence, loss of libido or infertility (1,3). Giant pituitary tumours (larger than 4 cm) are rare and most of them are nonfunctional. Giant prolactinomas with massive extrasellar extension are also rare and their clinical management is sometimes problematic. Radiological examinations are of great value in tumour evaluation.