Hand-assisted laparoscopic surgery for a mesenteric teratoma.

Mature cystic teratomas are benign neoplasms of germ cell tumors that occur most frequently in gonadal sites. The tumors usually contain 2 or 3 well-differentiated elements of endodermal, ectodermal, and mesodermal origin. Although relatively uncommon, teratomas can be composed of mature tissue originating from only 1 germ cell layer. This is known as a monodermal teratoma. Extragonadal teratomas, especially mesenteric teratomas, are extremely rare. Currently, only 21 cases of mesenteric teratoma have been described in the English literature. Mesenteric teratomas are rarely diagnosed preoperatively because pathological examination is necessary to make a definitive diagnosis. We herein report a rare case of mesenteric monodermal teratoma and review the literature. To the best of our knowledge, this is the first case of mesenteric teratoma treated with hand-assisted laparoscopic surgery.