[Skin tumor grown within an altarpiece from the 16th century].

Fragments of the so-called "Straußfurt Retable", temporarily acquired by Nazi leader Hermann Goering and therefore later suspected as looted art, are exemplary for problems of provenance investigation in poorly documented objects. The central shrine is a carved high relief showing the coronation of the virgin Mary. Damages from the end of WWII are described and illustrated in the literature. A very astonishing dermatologic finding, however, was never mentioned, or never seen: a large exophytic "skin"-colored tumor on the cheekbone of Christ, covered by the coherent original color layer with fine crevices in the basal edges. Only on closer examination does it become clear that the protrusion could not have existed in this location from the beginning. Its (relative!) growth is a result of "working" of wood fibers without cell proliferation, with nearly no longitudinal, but very considerable transverse shrinkage. This tumor represents masses of vertical fibers belonging to a branch that was above the surface of the wood. The starting point of the tumor growth was a "knot" in the Lime wood that would not have been suspected by the carver-500 years ago.