[Pathological diagnostics of CUP (Cancer of Unknown Primary)]

CUP (Cancer of Unknown Primary) is a relatively frequent cancer type causing incomparable difficulties in pathological diagnosis as compared to other tumor types. The primary may even remain unknown at authopsy due to microscopic size or previous regression. By applying the biological, epidemiological cancer information it is possible to compose rational pathological differential diagnostic algorithms to define with high probability the primary site of the cancer. The new molecular tests developed for CUP are very helpful especially if they are used in combination with pathological data.