Ossifying pituitary gonadotroph adenoma: A case report

Background. Bone formation in pituitary adenomas is a rare finding. Only tw o previous cases were published, occurring in a prolactin- producing and a growth hormone- producing pituitary adenoma respectively, both in pre-menop ausal women. Clinical Material. This is the third report of an ossified pituitary adenom a and the first report of a pituitary gonadotroph adenoma with bone formati on occurring in an elderly man. MRI imaging revealed an unusual eggshell ca p-like calcified structure surrounding the tumor. Histologically, the adeno ma contained irregularly anastomosing trabecules with well formed lacunae a nd osteoblasts along the margins. Conclusions. Insufficient tumor blood supply may trigger proliferation of c onnective tissue that subsequently undergoes osteoid metaplasia. Pituitary adenoma with osteoid metaplasia should be included in the differential diag nosis of calcifying tumors int eh sella region.