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Updated: May 27, 2026

Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas
Published on: January 17, 2018
Neuroendocrine tumor of unknown origin metastasizing to a growth hormone-secreting pituitary adenoma
Farshad Nassiri1, Michael Cusimano, Fabio Rotondo
1Division of Neurosurgery, St. Michael's Hospital, Toronto, Canada. farshad.nassiri@utoronto.ca
Background:
Metastasis of a neuroendocrine tumor to the anterior pituitary is extremely rare.
Methods:
A 55-year-old woman presented with features suggestive of acromegaly and bone and joint pain. A bone scan suggested metastatic disease. A biopsy of the lumbar spinal lesions revealed a neuroendocrine tumor. Magnetic resonance imaging of the sella demonstrated a lesion with parasellar and suprasellar extensions. Given the need for tissue diagnosis and optic compression, the sellar lesion was removed via transsphenoidal hypophysectomy.
Results:
Histology of the biopsy indicated two different tumors in close association. One showed histological features of a pituitary adenoma, whereas the other was a neuroendocrine carcinoma. The pituitary adenoma was immunopositive for growth hormone (GH), whereas the neuroendocrine carcinoma was immunopositive for serotonin and bombesin and immunonegative for GH.
Conclusions:
This is the first report of a serotonin and bombesin immunopositive neuroendocrine tumor of unknown primary origin metastatic to a GH-secreting pituitary adenoma, resulting in acromegaly.
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