Intraoral Immature Malignant Teratoma with No Evidence of Other Sites of Involvement in a 6-Year-Old Patient: A Case Report.

: Head and neck teratomas are embryonal tumors that develop when totipotent germ cells escape the developmental control of primary organizers and form a more-or-less organoid mass in which tissues from all three germ layers (ectoderm, endoderm, and mesoderm) can be identified. Mature teratomas may either transit into germ cell or non-germ cell malignancies or remain histologically mature with the possibility of growing, thus inducing certain complications when reaching a large size. This article aims to investigate a very rare case of a 6-year-old child who exhibited a recurrent intraoral mass with multiple conflicting biopsies. : A 6-year-old male patient was referred to the postgraduate clinic of the Department of Oral Medicine/Pathology, Dental School, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece, because his pediatric dentist noticed an exophytic, intraoral mass, distal to tooth #75 during a routine checkup. The first histopathological examination showed a gingival tumor, classified as a small round blue cell tumor, with greater similarity to adamantinoma-like Ewing sarcoma (ALES) and less to synovial sarcoma. The second pathologist examined the same tissue specimen and suggested the extremely rare presence of an immature malignant teratoma. Following chemotherapy, the rest of the teratoma with the adjacent tooth #75 was removed, and the histopathological examination showed a mature teratoma. : This case illustrates the crucial role of the dentist, and in this case of the pediatric dentist, to promptly diagnose the underlying disease. Genetic screening may assist in detecting high-risk populations. In such complex histopathological cases, the importance of cooperating with experienced oral and maxillofacial pathologists is highlighted. We describe a rare case of intraoral malignant teratoma, and an extended literature review revealed that our case is the first ever reported.