A macroscopic fluorescence illumination assembly is provided for use with an a imaging apparatus with a light-tight imaging compartment. The imaging apparatus includes an interior wall defining a view port extending into the imaging compartment to enable viewing of a specimen contained therein. The illumination assembly includes a specimen support surface sized and dimensioned for receipt in the imaging compartment, and oriented to face toward the view port of the imaging apparatus. The support surface is substantially opaque and defines a window portion that enables the passage of light there through. The window portion is selectively sized and dimensioned such that the specimen, when supported atop the support surface, can be positioned and seated over the window portion in a manner forming a light-tight seal substantially there between. The illumination assembly further includes an excitation light source, and a bundle of fiber optic strands having proximal ends thereof in optical communication with the light source. The distal ends of the strands terminate proximate the window portion of the support surface. The distal ends each emit a respective beam of light originating from the light source which are then collectively directed toward the window portion and into a bottom side of the specimen wherein the diffused light passes there through and exits a topside thereof for receipt through the view port to view the fluorescence of the specimen.