CD99 and neoplasm: Immunophenotyping found tumor cells that were CK (+), CD56 (+), Syn (+), EMA (+), β-catenin (membrane +), LCA (−), CD99 (−), S100 (−), HMB-45 (−), SOX-10 (−), TTF-1 (−), CDX-2 (−), and CD34 (−), along with a Ki-67 proliferation index of 60–70%.