Well-differentiated cerebellum within a mature cystic teratoma of the ovary.

Mature cystic teratoma is the most common benign neoplasm of the ovary, accounting for 27-44% of all ovarian tumors and up to 58% of benign ovarian tumors [1], and is composed of mature-appearing derivatives of two or three embryonal layers [2]. Ectodermal derivatives are observed in almost all mature teratomas [2]. Organized mature neural tissue is a common component. Glial tissue is the most common neural component of mature teratoma, and well-organized cerebrum and choroid plexus are also present [3]. However, presence of cerebellum is extremely rare in ovarian mature teratomas, and only 13 cases of mature cerebellar tissue within ovarian teratoma have been reported in the literature [4-8]. Herein, we describe the 14th documented case of well-differentiated cerebellar tissue in an ovarian mature cystic teratoma and review the literature.