Freshly excised or freshly frozen tissue for Raman analysis will be obtained from a dermatology practice affiliated with UMCB. In the course of the routine removal of benign or malignant tumors in the office, skin cancer surgeons routinely check frozen sections to ensure adequate margins are obtained. Consent will be obtained from patients to provide freshly excised or freshly frozen leftover tissue obtained during Mohs surgery to be discarded after histological diagnosis. Freshly excised tissue will be measured at the time of excision before processing, while the freshly frozen tissue samples will be stored in a freezer at the Mohs clinic and transferred to the UT- Austin campus for spectroscopic analysis.