RESUMO
BACKGROUND: Mature cystic teratomas are the most common form of ovarian tumor in children and adolescents. These tumors are mostly benign and non-secreting. Virilization from an ovarian teratoma is exceptionally rare in pediatrics. Equally rare is the association of ovarian teratomas with auto-immune encephalitis. METHODS: We describe the case of a 15-year-old girl with menstrual abnormalities and virilization, who had a past medical history of encephalitis of an unknown etiology 16 months prior to presentation. RESULTS: Endocrine evaluation revealed an elevated serum testosterone and 17-hydroxy progesterone. A large left ovarian tumor was seen on a CT scan. Surgical excision revealed a mature cystic teratoma containing 6 liters of clear fluid with high androgen levels. Antibodies to the N-methyl-D-aspartate receptor of the hippocampus were detected in pre-operatively archived serum, but undetectable 6 months postoperatively. Immunohistochemistry studies on the tumor sections revealed that the antibodies in the patient's serum reacted with areas of the tumor expressing the N-methyl-D-aspartate receptor. Postoperatively, the patient's menstrual cycles became regular and her behavioral problems resolved. Her testosterone levels fell precipitously as well. CONCLUSION: Both virilizing mature cystic teratomas and teratoma-associated encephalitis are extremely rare in the pediatric population. We report on the first instance of these 2 rare entities occurring in the same patient.
