Spindle cell nodule and peptic ulcer arising in a fully developed gastric wall in a mature cystic teratoma

We describe an ovarian mature cystic teratoma that contained a peptic ulcer arising from a fully developed gastric wall. Beneath the ulcer was a spindle cell nodule resembling a sarcoma. To our knowledge, neither peptic ulcer nor peptic ulcer associated with a sarcomalike spindle cell proliferation has been reported in ovarian teratoma, although there have been previous reports of full-thickness gastrointestinal wall development. Another interesting aspect of this case was peritoneal melanosis associated with brown-black pigmentation of the ovarian teratoma.