Photodynamic Diagnosis of Kidney Cancer Using Fluorescence Endoscopy and Oral 5-ALA

The goal of this prospective, single-arm feasibility study is to evaluate the safety and feasibility of using Gleolan® (5-aminolevulinic acid), an FDA-approved drug currently used during brain tumor surgery, in adults with suspected kidney cancer undergoing partial nephrectomy. Gleolan has shown promise in improving the visualization of cancerous tissue, and this study aims to assess its potential use in urologic oncology. The main questions it aims to answer are: * Is Gleolan safe and well tolerated in patients with suspected kidney cancer undergoing partial nephrectomy? * Is the use of Gleolan feasible for fluorescence-guided identification of kidney cancer lesions during surgery? Participants will: * Receive Gleolan before surgery according to the study protocol. * Undergo partial nephrectomy, during which fluorescence imaging will be used to evaluate the visualization of kidney tumor tissue. * Be monitored for safety outcomes and any adverse events before, during, and after surgery.

Inclusion Criteria: * Patients aged 18 or older * Has indications for standard-of-care partial nephrectomy * Able to provide informed consent * Able to comply with study requirements Exclusion Criteria: * Known porphyria or hypersensitivity to porphyrins * Pregnant or breastfeeding women * AST or ALT \> 2x upper limit of normal within 30 days prior to surgery * Participation in another investigational study within 30 days * Known allergy or contraindication to 5-ALA or its components