¿They are most often found in the vagina, cervix, and bladder. Endometriosis is a rare occurrence outside of the pericardium. Endom¿tr¿ has b¿¿n r¿¿¿rt¿d n th¿ liver, br¿n, lung, ¿nd ¿ld urg¿l ¿¿r. Endometrial mumps, although potentially problematic, are typically benign (i.e. non-cancerous).