Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Department of Oral Diagnostic Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Pathol Int. 2021 Jan;71(1):80-87. doi: 10.1111/pin.13036. Epub 2020 Oct 20.
Primordial odontogenic tumor (POT) is a newly classified, mixed epithelial and mesenchymal odontogenic tumor, with only 17 reported cases to date. Herein, we report a case of POT that occurred in the right maxilla of a 10-year-old boy and reveal unique features in comparison with those previously reported. Radiologically, the lesion presented as a well-defined, unilocular radiolucency with notable radiopaque foci on the periphery. Microscopically, the tumor was mainly composed of dental papilla-like myxoid fibrous connective tissue, largely surrounded by non-keratinized squamous epithelium with numerous calcified particles, and partly enclosed by inner enamel epithelium-like columnar cells and enamel organ-like structures accompanied with cuboidal and/or stellate reticulum-like cells. Immunohistochemically, the epithelium tested positive for cytokeratin 14 and 19. Moreover, amelogenin and ameloblastin, matrix proteins relating to enamel formation, were positive in the covering epithelium. The tumor was enucleated as a whole, and no recurrence was recorded thereafter. Although the presence of numerous calcified particles was unique, we diagnosed this lesion as POT based on the above-described features. Furthermore, we emphasize the importance of the differential diagnosis of POT and other odontogenic tumors that resemble corresponding tooth germ components.
原发性牙源性肿瘤（POT）是一种新分类的、混合上皮和间叶性牙源性肿瘤，迄今为止仅报道了 17 例。本文报道了 1 例发生在 10 岁男孩上颌右侧的 POT 病例，并与以往报道的病例进行了比较，揭示了其独特的特征。影像学上，病变表现为界限清楚的单房性透亮影，周边有明显的不透射线灶。显微镜下，肿瘤主要由牙乳头样黏液纤维结缔组织组成，大部分被无角化复层鳞状上皮包围，上皮内有大量钙化颗粒，部分被内釉上皮样柱状细胞和牙器样结构包围，伴有立方状和/或星状网状细胞。免疫组化染色显示，上皮细胞角蛋白 14 和 19 阳性。此外，覆盖上皮中与釉质形成相关的基质蛋白牙本质蛋白和釉原蛋白呈阳性。肿瘤被整块切除，此后无复发。尽管存在大量钙化颗粒是独特的，但根据上述特征，我们诊断该病变为 POT。此外，我们强调了 POT 与其他类似相应牙胚成分的牙源性肿瘤的鉴别诊断的重要性。
