“…This was probably the first report of EPSCC. Since then, the primary site of EPSCC has been documented in multiple organs, such as the head, esophagus, stomach, pancreas, bladder, kidney, prostate, cervix and breast [6,7]. In few cases, the primary site remained undetected and theses tumors were classified as small cell carcinoma of unknown primary (SCUP), which were always grouped with EPSCC, constituting nearly 7-30 % of EPSCCs [8].…”