Original ArticlesNew Clinicopathologic Scenarios of EBV+ Inflammatory Follicular Dendritic Cell Sarcoma Report of 9 Extrahepatosplenic CasesJiang, Xiang-Nan MD*,†; Zhang, Yan MD, PhD*,†; Xue, Tian MD*,†; Chen, Jie-Yu MD, PhD‡; Chan, Alex C.L. FRCPA§; Cheuk, Wah FRCPA§; Chan, John K.C. FRCPA§; Li, Xiao-Qiu MD, PhD*,† Author Information *Department of Pathology, Fudan University Shanghai Cancer Center †Department of Oncology, Shanghai Medical College, Fudan University, Shanghai ‡Department of Pathology, Nanjing Drum Tower Hospital, Nanjing §Department of Pathology, Queen Elizabeth Hospital, Hong Kong SAR, China 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: Xiao-Qiu Li, MD, PhD, Department of Pathology, Fudan University Shanghai Cancer Center, 270 Dong-An Road, Shanghai 200032, China (e-mail: [email protected]). The American Journal of Surgical Pathology 45(6):p 765-772, June 2021. | DOI: 10.1097/PAS.0000000000001632 Buy Metrics Abstract EBV+ inflammatory follicular dendritic cell (FDC) sarcoma is an indolent malignant neoplasm of spindled FDCs with a rich lymphoplasmacytic infiltrate and a consistent association with Epstein-Barr virus (EBV). It occurs exclusively in the liver and spleen, with the exception of a few colonic examples. In this study, we report 9 extrahepatosplenic cases, including 4 occurring in previously undescribed sites, but all apparently anatomically related to the aerodigestive tract. The cases included 5 gastrointestinal tumors all presenting as colonic pedunculated polyps, 2 presenting as mesocolon mass, and 2 involving the palatine or nasopharyngeal tonsils. One patient with a colonic tumor was complicated by paraneoplastic pemphigus. The patients had a median age of 58 years, with female predominance (female:male=7:2). A favorable outcome was observed in 7 patients. Histologically, EBV+ inflammatory FDC sarcomas arising from these anatomic sites were similar to their hepatosplenic counterparts. Spindled to oval neoplastic cells with ill-defined cell borders were dispersed or formed loose whorled fascicles in a dense lymphoplasmacytic background. They had vesicular nuclei with distinct nucleoli and typically exhibited a range of nuclear atypia in the same case. The neoplastic cells showed variable expression of FDC markers and were labeled for Epstein-Barr virus–encoded RNA on in situ hybridization. These 9 cases thus broaden the clinicopathologic scenarios of EBV+ inflammatory FDC sarcoma. Recognition of the potential existence of this tumor type in extrahepatosplenic sites permits a correct diagnosis to be made. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.