Rare case of complete colon structure in a mature cystic teratoma of the ovary in menopausal woman: a case report

BACKGROUND Mature cystic teratoma (MCT) of the ovary is benign germ cell tumor and shows the highest incidence in women of reproductive age. Histologically, it includes components derived from endoderm, mesoderm, and ectoderm. Although there have been many reports of MCT having small part of the intestinal component, ovarian MCT containing complete colon structure was very rare. CASE PRESENTATION A 54-year-old woman underwent laparoscopic left salpingo-oophorectomy due to an incidentally found ovarian mass. The pathologic diagnosis of the ovary was MCT containing complete colonic structure. The colonic wall exhibited complete structure of the large intestine composed of mucosa, submucosa, proper muscle, subserosa and serosa. It also contained sebaceous gland, sweat glands, fat tissue, and bone. The patient recovered without any complications. CONCLUSION Immunohistochemical staining can be used for differential diagnosis between MCT with colonic wall and mucinous tumor. We report a very rare case of MCT that had complete colon structure with a brief literature review.