[A case of TSH-secreting pituitary adenoma associated with an unruptured aneurysm: successful treatment by two-stage operation and gamma-knife].

We report a successfully treated case of invasive TSH-secreting pituitary adenoma associated with an unruptured internal carotid artery aneurysm by two-stage operation and gamma-knife radiosurgery. A 64-year-old woman was admitted to our department with a 3-year history of general fatigue and 1-year history of anxiety, palpitation and hyperhydrosis. Endocrinological examination revealed hyperthyroidism with elevated TSH, GH and somatomedin C. Magnetic resonance images demonstrated a tumor in the sella turcica which extended into the left cavernous sinus, furthermore, indicated aneurysm-like flow void at the ventral part of the left internal carotid artery. The aneurysm was confirmed by conventional angiography. Neck clipping of the aneurysm was performed through pterional approach as the first operation. One month later, at the second operation, the pituitary adenoma except for cavernous sinus portion was resected via the transsphenoidal approach. Immunohistological examination revealed positive for TSH and GH. Gamma-knife radiosurgery with a central dose of 33.3 Gy and peripheral dose of 17 Gy was carried out for residual tumor at the cavernous sinus under both MRI and CT guidance. Posttreatment course was uneventful with normalization of thyroid function at 16 months after gamma-knife. Two-stage operation and gamma-knife radiosurgery is effective for TSH-secreting adenoma extending into the cavernous sinus associated with an unruptured aneurysm.