Giant Invasive Pituitary Adenoma

Pituitary adenomas are the third-most common intracranial tumor after meningiomas and gliomas. Some adenomas are typical, but others may be invasive, aggressive, premetastatic or carcinomatous. Invasive adenomas can infiltrate bone, dura, nasal sinuses, cranial nerves, and venous sinuses. The goal of surgery in the invasive nonsecretory adenomas is gross total resection, followed by radiotherapy, radiosurgery, or conservative follow-up. In the invasive secretory group, surgery is followed by medical treatment, radiotherapy, or radiosurgery.

We are presenting our experience with giant invasive pituitary adenomas in the period between 1985 and 2008. Fifty-six patients were encountered: 33 men and 23 women. Age of patients ranged from 16–68 years with mean age of 36.7 years. Main presentation was visual failure and endocrinological manifestations.

Thirty-six patients had nonsecreting adenomas, 16 had prolactin secreting adenomas, 2 had ACTH, and 2 had GH secretion. Fifty patients needed transcranial and eight patients needed transnasal surgical excision. Indication of surgery in nonfunctioning adenoma was neurosurgical deterioration. In the secretory group, indication was deterioration of neurological condition in spite of medical treatment. Transcranial surgery was needed where invasive adenoma extended to posterior, middle, or anterior fossa. One of our preferred surgical approaches is transbasal subfrontal, but others are also favored. The aim of surgery was gross total resection whenever possible. Postoperative adjuvant therapy was needed for all patients: radiotherapy in 54 patients, gamma radiosurgery in 12 patients, and drug therapy in 12 patients. The dose in gamma knife varies between 14 and 22 Gy. Follow-up in our patients ranged from 20–154 months, with a mean follow-up period of 58.2 months. Mortality in this series occurred in two patients—one patient died of meningitis after major CSF leak and one died of pulmonary embolism. No carcinomatous change was seen in any of our patients.

We believe that surgical cure is not possible for all invasive secretory and nonsecretory adenomas. Invasiveness is an issue decided by radiological, histological, and operative findings. Most invasive adenomas are giant ones.