IMMATURE OVARY WITH COMPONENT TERATOMA) TERATOMA OF A NEURAL ("SOLID" THE A Clinicopathologic Study of 20 Cases Francisco F. Nogales, Jr., M.D.,? Blaise E. Favara, M.D.,- Francis J. Major, M.D.,w and Steven G. Silverberg, M.D.]I Abstract Twenty cases of immattu'e teratolna of the ovary with a neural component are analyzed. A plea is made for use of the nonmnclature adopted from the new World Heahh Organization classification of ovarian tumors, and past confusion over terminology and histogenesis of this rare tumor is discussed. All the primm'y tumors in the present series contained at least some im- mature tissues (predominantly of neural origin) and were thus graded from 1 to 3 according to the criteria of Thurlbeck and Scully. No grade 0 tunlors ("benign solid teratomas") were identified. We believe that thorough Sectioning ahnost always insures the identification of immature elements. The prognosis was closely relate(l to the histologic grade, but con'elated poorly with the clinical stage, the latter being influenced by the COlilillon finding (25 per cent of the cases in this series) of peritoneal implants composed exclusively of mature glial tissue, which is associated with a benign clinical evolution. This phenomenon of maturation or differentiation appears to be the rule rather than the exception in this tumor, since implants are usually of better or equal differentiation when compared with their l)rimar) 9 tumors and older patients tend to have lower grade tttlnors than younger patients. Since the majority of patients with this tumor are young, primary surgical therapy should be conservative, unilateral salpingo- oophorectonl)' often being sufticient. Spontaneous or operative rupttn'e of the *Study supported in part by grants CA-15823, CA-17060, and XA-12247-04 fiom tile National Cancer Institute. %\ssociate l'rol'essor ot"Pathology, Universityof SevilleFacultyof Medicine, Seville,Spain. $Ch;,Ih'man, Delmrtment of Patholog)', Children's llospital, 1)cnver, Colorado. w Clinical l'rofessor of Obstetrics and Gynecology, University of Colorado School of Medicine. I)irector of Gynecologic Oncology, I)enver General tlospital, I)enver, Colorado. [[Associate l'rofessor of l'athology and Director of Surgical Pathology, University of Colorado School of Medicine. Executive Director, Colorado Regional Cancer Center, I)enver, Colorado. 625