Immunohistochemical characteristics of mature ovarian cystic teratomas in patients with postoperative recurrence.

Because a mature teratoma could recur, we studied the clinical, pathological, and immunohistochemical characteristics of mature ovarian cystic teratomas of 121 patients who underwent surgeries between 1994 and 2002. Recurrence was defined as cases that required secondary surgeries for mature ovarian cystic teratomas. A total of 10 patients were grouped as recurrence, and 111 patients were grouped as non-recurrence. The recurrence group was generally younger (mean, 22.9 +/- 1.26 vs. 32.8 +/- 1.15 years; p < 0.05), had higher tridermal components, and had greater central nervous system (CNS) component expression rate (9 vs. 48%, p < 0.05) compared with the non-recurrence group. The time between primary and secondary surgery averaged 9 years. Our result showed that maturation of teratomas reduced the number of neurons and increased glia. The process is similar to the aging process of brains. The presence of tridermal components and a high synaptophysin/glial fibrillary acidic protein (SP/GFAP) ratio suggested that recurrent ovarian teratomas were capable of both neuronal and glial differentiations. Nestin was expressed in the astrocyte from both the recurrence and non-recurrence groups. Thus, we concluded that nestin was not a useful marker for predicting recurrence and that attention should be given when a high ratio of SP/GFAP is found in lesions.