5-Aminolevulinic Acid (5-ALA) was approved by the FDA as an intraoperative optical imaging agent in patients with suspected high-grade gliomas (HGGs) in 2017. The investigators plan to administer 5-ALA to patients with pituitary tumors to demonstrate whether it can be used as an intraoperative optical imaging agent for this pathology. Overall, this pilot study will afford the overall opportunity to improve surgical management and advancement of the science of neurological and neuroendocrine disease.

Inclusion Criteria:

• Patients with non-functioning pituitary adenomas who require surgical intervention, as deemed appropriate by a neurosurgeon, either due to size criteria, observed growth in lesion on MRI, and/or for alleviation of the symptoms of mass effect.
• Patients with functional pituitary adenomas, including prolactinomas, growth-hormone secreting adenomas, and ACTH-secreting adenomas, where surgery is recommended for biochemical control. Patients with symptoms of Cushing's Disease and centralization of ACTH on IPSS without imaging-confirmed lesions will be included in the study.

Exclusion Criteria:

• History of allergic reactions attributed to compounds of similar chemical or biologic composition to aminolevulinic acid (ALA). Patients should refrain from use of other potential phototoxic substances (e.g. tetracyclines, sulfonamides, fluoroquinolones, hypericin extracts) for 72 hours.
• Personal or family history of porphyria.
• Uncontrolled concurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with 5-ALA breastfeeding should be discontinued if the mother is treated with 5-aminolevulinic acid.
• Women who are pregnant or become pregnant will be excluded from the trial as it is unknown if aminolevulinic acid (ALA) is teratogenic or has abortifacient effects.
• Prior history of GI perforation, diverticulitis, and/or peptic ulcer disease.

The investigators will study patients with pituitary macroadenomas who require surgical intervention, as deemed appropriate by a neurosurgeon, either due to size criteria, observed growth in lesion on MRI, and/or for alleviation of the symptoms of mass effect. The investigators will also study patients with functional pituitary adenomas, including prolactinomas, growth-hormone secreting adenomas, and ACTH-secreting adenomas, where surgery is recommended for biochemical control.