Methods and systems for in vivo classification of tissue are disclosed. The tissue is irradiated with light from multiple light sources and light scattered and fluoresced from the tissue is received. Distinct emissions of the sample are identified from the received light. An excitation emission matrix is generated (1002). On-diagonal and off diagonal components of the excitation emission matrix are identified (1004, 1006, 1008). Spectroscopic measures are derived from the excitation emission matrix (1014), and are compared to a database of known spectra (1016) permitting the tissue to be classified as benign or malignant (1018). An optical biopsy needle or an optical probe may be used to contemporaneously classify and sample tissue for pathological confirmation of diagnosis.