Wiley Acta Medica Okayama 2050-0904 9 6 2021 A case of langerhans cell histiocytosis of the mandible that spontaneously regressed after biopsy in a child e04321 EN Kisho Ono Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Tatsuo Okui Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Yuki Kunisada Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Kyoichi Obata Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Masanori Masui Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Shoji Ryumon Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Soichiro Ibaragi Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Tomoya Nakamura Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Akira Sasaki Department of Oral and Maxillofacial Surgery, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine In younger patients of LCH, we should consider that the effectiveness of follow-up without aggressive treatment for SS-type LCH in the oral and maxillofacial bone. However, there are very rare case in which an SS-type LCH recurred after showing a healing tendency. Regular follow-up must be performed even after healing. No potential conflict of interest relevant to this article was reported.