Original ArticlesSertoli-Leydig Cell Tumors of the Ovary With Follicular Differentiation Often Resembling Juvenile Granulosa Cell Tumor A Report of 38 Cases Including Comments on Sex Cord-Stromal Tumors of Mixed Forms (So-called Gynandroblastoma)Ordulu, Zehra MD; Young, Robert H. MD, FRCPathAuthor Information James Homer Wright Pathology Laboratories, Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Robert H. Young, MD, FRCPath, James Homer Wright Pathology Laboratories, Department of Pathology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114. (e-mail: [email protected]). The American Journal of Surgical Pathology: January 2021 - Volume 45 - Issue 1 - p 59-67 doi: 10.1097/PAS.0000000000001544 Buy Metrics Abstract Thirty-eight ovarian Sertoli-Leydig cell tumors that contained follicles are described; in 33 of them follicles imparted a microscopic appearance resembling that of the juvenile granulosa cell tumor. The average age of the patients (28 y), frequency of androgenic manifestations (40%), and dominant histopathologic features were all typical of Sertoli-Leydig cell tumor, mostly (80%) of intermediate differentiation. The remaining tumors were poorly differentiated; none were well differentiated. The follicles that mimicked juvenile granulosa cell tumor accounted for ∼5% to 40% of the tumor volume. They typically arose out of the characteristic lobules seen in Sertoli-Leydig cell tumors of intermediate differentiation. There appeared to be a gradual loosening of the stroma imparting a pale appearance to the lobules and on that background follicles emerged. The follicles were mostly relatively regular and round to oval with basophilic or eosinophilic secretion and when fully formed perfectly mimicked juvenile granulosa cell morphology. In 18 of these cases, and 5 others, follicles were present that had a nonspecific morphology and had a random, nonlobule-associated distribution. The presence of a juvenile granulosa-like appearance often raised consideration of the diagnosis of a sex cord-stromal tumor of mixed forms (so-called gynandroblastoma) but a multifocal origin within lobules of otherwise typical Sertoli-Leydig cell tumors, and overall tumor characteristics indicates aberrant differentiation within the latter tumor of a nature only sporadically noted in the prior literature. Such neoplasms should, in our opinion, not be placed in the grouping of a sex cord-stromal tumor of mixed forms but rather in the Sertoli-Leydig category. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.