EMERGENCE OF MATURE TERATOMA FOLLOWING TREATMENT OF SACROCOCCYGEAL ENDODERMAL SINUS TUMOR - CT AND MR-IMAGING WITH PATHOLOGICAL CORRELATION

We report a case of pseudoretroconversion in which, clinically and pat hologically, it appeared that an endodermal sinus tumor retroconverted to mature teratoma. An 8-month-old white female infant with a sacroco ccygeal tumor, diagnosed by biopsy as endodermal sinus tumor (yolk sac tumor), was treated with chemotherapy. The residual tumor after treat ment was mature teratoma confirmed by imaging and by pathological exam ination. We present the computerized tomography (CT) and magnetic reso nance imaging (MRI) findings with pathological correlation.