In the case of sporadic CMTC, this pathway can also be activated by somatic APC mutations or mutations in CTNNB1. As a consequence, β-catenin shows immunohistochemically an aberrant nuclear expression, especially in the squamoid morules, a fact that is used as an immunohistochemical diagnostic hallmark for this tumor [1, 2, 8]. Here, APC is linked to neoplasm.