Non-functioning pituitary adenomas are the most frequent type of pituitary tumors, defined by the lack of hormonal overproduction from the tumor. Non-functioning macroadenomas are > 1 cm in size that can cause progressive visual loss, headaches, and symptoms of pituitary dysfunction (hypopituitarism and/or hyperprolactinemia). Initial treatment for these type of tumors is trans sphenoidal surgical resection. In cases where the outcome is incomplete surgical resection of the tumor, repeat surgery and external beam radiation therapy may be performed. Previous clinical work suggests there may be a role for a folate receptor in the treatment of non-secretory, pituitary adenomas. MORAb-003 is a monoclonal antibody that has the potential to be an effective agent against resectable, non-functioning pituitary adenomas. MORAb-003 has been shown to be well tolerated. This study allows the opportunity to determine if therapy with farletuzumab is effective and safe.