Extraordinary Case ReportA Case of Dendritic Cell Neurofibroma With PseudorosettesKubota, Riko; Nishida, Haruto MD, PhD; Kodo, Yoshihiko MD; Oyama, Yuzo MD; Kusaba, Takahiro MD; Kadowaki, Hiroko MD; Arakane, Motoki MD; Daa, Tsutomu MD, PhDAuthor Information Department of Diagnostic Pathology, Faculty of Medicine, Oita University, Yufu, Japan. Correspondence: Haruto Nishida, MD, PhD, Department of Diagnostic Pathology, Faculty of Medicine, Oita University, Idaigaoka 1-1, Hasama-machi, Yufu, Japan 879-5593 (e-mail: [email protected]). The authors declare no conflicts of interest. The American Journal of Dermatopathology: August 2020 - Volume 42 - Issue 8 - p 604-607 doi: 10.1097/DAD.0000000000001613 Buy Metrics Abstract Dendritic cell neurofibroma with pseudorosettes (DCNP) is a rare benign peripheral nerve sheath tumor. Till date, 34 cases of DCNP arising from various sites have been reported. Histopathologically, DCNP is known to present with characteristic pseudorosettes, in which a type II cell is surrounded by type I cells. In the present report, we discuss the rare case of a 63-year-old man diagnosed with DCNP on the left flank (size: approximately 10 mm). On microscopic examination of the resected lesion, we observed the characteristic pseudorosettes with centrally placed type I cells, which exhibited small, dark, slightly irregular oval nuclei with nuclear inclusions, surrounded by type II cells, which showed a large pale nucleus with a constriction, a small nucleolus, and mildly eosinophilic cytoplasm. The type II cells were positive for S-100, CD57, LAMP2, fascin, and factor XIIIa. Although previous reports have suggested that type II cells exhibit a dendritic form, our immunohistochemical analyses revealed that these cells were dermal interstitial dendritic cells. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.