Adenomyosis with a sex cord‐like stromal element

A case of adenomyosis with a sex cord‐like stromal element is described. The element was an incidental, solitary, microscopic finding in a focus of adenomyosis. It was characterized by cord and trabecular arrangements of round to polygonal shaped cells in the endometrioid stroma. The cells were immunohistochemically positive for desmin and alpha‐smooth muscle actin but negative for sex cord markers (alpha‐inhibin and O13). The element appears to originate from the endometrial stromal cells through smooth muscle metaplasia.