The patient went on to have a transsphenoidal hypophysectomy and resection.
Histology
MICROSCOPIC DESCRIPTION: The sections show a moderately cellular pituitary adenoma comprising nests, surrounded by vascularised stroma. The tumour cells have mildly enlarged round nuclei, finely granular chromatin and moderate amounts of eosinophilic cytoplasm. There are no atypical features. Very small amount of normal anterior pituitary gland tissue is present in specimen 3. The tumour cells are positive for FSH and SF-1. The Ki-67 index is about 2%. Immunostains for prolactin, TSH, LH, ACTH and GH are negative.
FINAL DIAGNOSIS: Silent gonadotroph adenoma.