[Clinicopathological features of basal cell type dysplasia of esophagus]

Objective: To investigate the clinicpathological features of basal cell type dysplasia of the esophagus. Methods: The clinicopathological data of 71 cases of basal cell type dysplasia of esophagus were collected at the People's Liberation Army Joint Logistics Support Force 989 Hospital, from 2009 to 2019, and the histomorphologic characteristics and immunophenotype were evaluated. The relevant literature was reviewed. Results: The ratio of male to female patients was 1.6∶1.0, and the median age was 65 years (range 48-81 years). The tumors were located in the upper segment of the esophagus in four cases (5.6%), the middle segment in 54 cases (76.1%), and the lower segment in 13 cases (18.3%).The median maximal tumor diameter was 12.0 mm (range 3-42 mm). According to Paris Classification, 0-Ⅱb accounted for 42.3% (30/71) of the cases. Under endoscope, the lesions were reddish with abnormal mucosal microvessels. Histologically, the neoplastic cells were small, with a high nuclear-cytoplasmic ratio, similar to basal cells, and uniform in morphology. The structural atypia was characterized by dense and disordered tumor cells, loss of basal cell polarity, and absence of normal squamous differentiation gradient. In 10 cases, the tumors were confined to the lower part of the epithelium. The tumor cells were smaller and more uniform in shape, and extend to the superficial lamina propria. Sixty-one tumors involved at least the entire layer of the upper cortex. There were 31 cases of neoplasms with superficial invasive carcinoma. The types of neoplasms included typical squamous cell carcinoma, basaloid squamous cell carcinoma, small cell neuroendocrine carcinoma, squamous cell carcinoma with sebaceous adenoid carcinoma, and differentiation of glandular/ductal epithelioid carcinoma. Immunohistochemical staining showed that the mutant expression rate of p53 protein was 41.5% (17/41). All 41 cases (100.0%) showed abnormal distribution pattern of Ki-67. According to the initial pathologic diagnosis, there were 18 cases of low grade dysplasia, 12 cases of atypical epithelial cells, and 41 cases of high grade dysplasia and superficially invasive carcinoma. Conclusions: Basal cell type dysplasia has unique morphologic characteristics and represents a tumor subtype in the morphologic lineage of esophageal squamous dysplasia. Tumor cells of basal cell type dysplasia, especially those distributed only in the lower part of the stratified squamous epithelium, may be tumor stem cells at the earliest stage of esophageal carcinogenesis and have multidirectional differentiation potential. When the tumor is confined to the lower part of the stratified squamous epithelium, it does not meet the diagnostic criteria for esophageal squamous dysplasia as defined by the current WHO classification.