There is a growing interest on fluorescence lifetime imaging techniques for medical diagnosis. Those techniques are often able to identify early-stage lesions in tissues even when fluorescence steady state-based techniques fail to provide any contrast. It is essential to develop fluorescence lifetime imaging instruments that can be used for in vivo applications. We report the development of a fast multispectral fluorescence lifetime rigid endoscope for in vivo imaging. Preliminary results show the potential to identify precisely the borders of some human skin lesions. In this paper, we present the details of the instrumentation and dataset analysis, and a result illustrating the system capabilities.