Immunostaining findings of alpha-smooth muscle actin (α-SMA) (+) (Fig. 5c), desmin (+), c-kit (−), cluster of differentiation CD34 (−), discovered on GIST protein 1 (DOG1) (−), S-100 proteins (−), and CD68 (−) suggested leiomyoma of the sigmoid mesentery, and weak positivity for the estrogen receptor (ER) and strong positivity for the progesterone receptor (PgR) confirmed the pathological diagnosis of PL (Fig. 5d). The gene discussed is ESR1; the disease is leiomyoma.