Müllerian lesions may present as mural small intestinal masses. These include endometriosis, which is discussed in detail in Chapter 13, and endocervicosis. Endocervicosis is the presence of benign endocervical glands in ectopic sites. It most typically involves the pelvic peritoneum and lymph nodes but it can present in the small intestine. In this site it presents as a mural nodule that on cut surface consists of variably shaped glands filled with mucin and lined by endocervical-type epithelium. The glands are surrounded by fibrous tissue or the smooth muscle fibers of the muscularis propria. Endometrial-like stroma is not present. The epithelium, which lacks any nuclear atypia, has a CK7+ CK20- phenotype (650).