This patient went on to have transphenoidal surgery.
Microscopic Description: Sections show pieces of a pituitary adenoma, and fragments of neurohypophysis. Focal microcysts are seen. The tumor cells are immunoreactive for growth hormone, and are immuno-negative for LH, TSH and FSH. Rare cells display immunoreactivity for ACTH and prolactin.
Final Diagnosis: Pituitary macroadenoma, showing growth hormone immunoreactivity.