Inclusion Criteria:  Subjects included in this trial must have had documentation of a new or recurrent head and neck or skull base tumor for which surgical resection is indicated and has been planned. These patients will include those with newly diagnosed or recurrent malignancies. Age 18-80 Karnofsky score >60%  Subjects must have normal organ and marrow function as defined below:  leukocytes ≥ 3,000/mcL absolute neutrophil count ≥ 1,500/mcL platelets ≥ 100,000/mcl total bilirubin within normal institutional limits AST(SGOT)/ALT(SPGT) ≤ 2.5 X institutional upper limit of normal creatinine within normal institutional limits OR Creatinine clearance >60 mL/min/1.73m2 for patients with creatinine levels above institutional normal as defined per institution. The effects of Gleolan® (5-ALA) on the developing human fetus are unknown. For this reason, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. A pregnancy test will be performed for all women of childbearing ability prior to surgery (see Exclusion Criteria below). Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. Ability to understand and the willingness to sign a written informed consent.  Exclusion Criteria:  Patients with non-resectable tumors or not deemed surgical candidates History of allergic reactions attributed to compounds of similar chemical/biologic composition to ALA. 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 Women who are pregnant or become pregnant will be excluded from the trial as it is unknown if ALA is teratogenic or has abortifacient effects. 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-ALA. Prior history of GI perforation, diverticulitis, and or/peptic ulcer disease