Question: My doctors are having trouble finding the location of my tumor. Is it common for a pituitary tumor not to show on an MRI and what techniques are used to find ectopic tumors?

Answer: We cannot visualize the pituitary tumor by MRI in about 40% of the patients. We can confirm its presence in the pituitary gland in almost all patients however by doing inferior petrosal sinus sampling. For ectopic ACTH-secreting tumors, we use CT and MRI imaging and the newly developed Octreotide scan. Despite this formidable technology we still fail to detect about 30% of ectopic tumors.

By Dr. George Chrousos MD (December, 1998)