Endoscopic features and associated histology of an basaloid squamous cell carcinoma of the esophagus at the very early stage

BACKGROUND: Basaloid squamous cell carcinoma of the esophagus (BSCCE) is generally detected at advanced stage and the prognosis is poorer than advanced conventional esophageal squamous cell carcinoma. Therefore, early detection is a critical to improve patients’ survival. However, only a few cases of early BSCCE have been reported and the endoscopic features of early BSCCE are not well described. We herein report the endoscopic features and associated histology of an early BSCCE limited within the mucosal lamina propria (m2). To our knowledge, this is the earliest BSCCE reported to date. CASE PRESENTATION: A 62-year-old male patient was admitted to our hospital because of epigastric pain for 3 months. White light endoscopy revealed a flat lesion with mild sloping at the periphery. The lesion was covered with leukoplakia, and normal vascular network could not be seen in the lesion. Magnifying endoscopy with narrow-band imaging showed abnormal intra-papillary capillary loop categorized as type B1 according to the classification of the Japan Esophageal Society. Iodine staining revealed a less-stained lesion. The lesion was completely resected through endoscopic submucosal dissection. Histopathologically, tumor cells, which were limited within the mucosal lamina propria, formed solid nests and lobule structures, with ribbon-like arrangement of sparse cytoplasm and round to ovoid hyperchromatic nuclei. A final diagnosis of early BSCCE was established. CONCLUSIONS: This is the earliest BSCCE reported to date. The prominent lesion with a gentle rising slope and less-staining or abnormal stain might be initial feature of early BSCCE.