In skeletally mature individuals, a growth hormone secreting adenoma results in acromegaly. In the skeletally immature, in whom long bones can continue to grow, gigantism is the result. 

The patient went on to have a transsphenoidal resection. 

Histology

MICROSCOPIC DESCRIPTION: The sections show a moderately cellular pituitary adenoma comprising sheets and nests, surrounded by vascularized stroma. The tumor cells have mildly enlarged round nuclei, finely granular chromatin and moderate amounts of eosinophilic cytoplasm. There are no atypical features. Normal anterior pituitary gland tissue is present in specimen 5. About 80% of the tumor cells are positive for growth hormone immunostain with weak to moderate intensity. About 20% of the tumor cells are also prolactin positive with moderate intensity. The Ki-67 is 1-2%. Immunostains for the other pituitary hormones are negative.

FINAL DIAGNOSIS:

Growth hormone secreting pituitary microadenoma.