Original ArticlesCriteria for Risk Stratification of Vulvar and Vaginal Smooth Muscle Tumors An Evaluation of 71 Cases Comparing Proposed Classification SystemsSayeed, Sadia MD*; Xing, Deyin MD, PhD†; Jenkins, Sarah M. MS‡; Weisman, Paul S. MD§; Buehler, Darya MD§; Warmke, Laura MD∥; Uram-Tuculescu, Cora MD∥; Bakkum-Gamez, Jamie N. MD¶; Howitt, Brooke E. MD#; Cortese, Cherise MD**; Park, Kay J. MD††; Schoolmeester, J. Kenneth MD* Author Information Departments of *Laboratory Medicine and Pathology ‡Health Sciences Research ¶Obstetrics and Gynecology, Mayo Clinic, Rochester, MN †Department of Pathology, The Johns Hopkins Hospital, Baltimore, MD §Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI ∥Department of Pathology, Virginia Commonwealth University, Richmond, VA #Department of Pathology, Brigham and Women’s Hospital, Boston, MA **Department of Laboratory Medicine and Pathology, Mayo Clinic, Jacksonville, FL ††Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 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: J. Kenneth Schoolmeester, MD, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street, Rochester, MN 55905 (e-mail: [email protected]). The American Journal of Surgical Pathology: January 2018 - Volume 42 - Issue 1 - p 84-94 doi: 10.1097/PAS.0000000000000920 Buy SDC Metrics Abstract Accurate risk stratification of smooth muscle tumors (SMTs) is essential for appropriate patient management. Yet, the rarity of SMTs of the vagina and vulva makes development of a prognostically meaningful classification system challenging. While 2 classification methods for vulvar SMTs and 1 for vaginal SMTs have been proposed, it is our experience that many pathologists tend to apply criteria for uterine SMTs when evaluating vulvovaginal tumors. We retrospectively reviewed a large cohort of vulvovaginal SMTs with clinical follow-up and evaluated which method most accurately classified tumors according to patient outcome. A total of 71 tumors, 53 vaginal (75%) and 18 vulvar (25%), from 71 patients were identified. All tumors were centrally examined for degree of cytologic atypia, morphology (spindled, epithelioid, myxoid), mitotic index per 10 high power fields, atypical mitotic figures, tumor cell necrosis, ischemic necrosis, tumor interface (circumscribed or infiltrative) and margin status. Clinical features were recorded for each patient. Follow-up was available for 63 patients (89%), and ranged from 1 to 234 months (median: 64 mo). While site-specific and uterine criteria showed equally excellent sensitivity in classifying smooth muscle neoplasms as leiomyosarcoma according to patient outcome, uterine criteria showed improved specificity relatively to site-specific methods in classifying tumors as nonsarcoma according to patient outcome. We recommend that uterine SMT criteria and nomenclature be adopted for evaluation and classification of vulvovaginal SMTs. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.