Histological diversity in basaloid squamous cell carcinoma of the esophagus

Basaloid squamous cell carcinoma of the esophagus (BSCCE) is a distinct variant of esophageal cancer. This study investigated histopathological variations of BSCCE. Thirty-eight surgical and two endoscopically resected specimens of BSCCE were examined. Histological features were classified into five components: solid nest (SN), microcyst and/or trabecular nest (MT), ductal differentiation (DD), cribriform pattern (CP), and an invasive squamous cell carcinoma (SCC) component. The immunohistochemical phenotypes of each component were examined using antibodies against cytokeratin (CK) 7, CK14, and alpha smooth muscle actin (SMA). SN, MT, DD, CP, and SCC were present in 95.0, 97.5, 27.5, 32.5, and 82.5% of the cases, respectively, and combinations of SN & MT, SN & DD, SN, MT & DD, SN, MT & CP, and SN, MT, DD & CP were found in 50.0, 2.5, 10.0, 17.5, and 15.0%, respectively. All the intraepithelial lesions observed in 18 (45.0%) cases were SCC. Immunoreactivity for CK7, CK14, and SMA was seen in 10.5, 86.8, and 18.4% of SN; 30.8, 97.4, and 38.5% of MT; 54.5, 100.0, and 54.5% of DD; 7.7, 76.9, and 23.1% of CP; and 6.1, 97.0, and 0.0% of SCC, respectively. CK14 immunoreactivity was seen in the periphery of most of the SN component. CK7, CK14, and SMA immunoreactivity was seen in the inner layer, all layers, and the outer layer of DD, respectively. MT and CP showed partial peripheral positivity for CK14 and SMA in microcystic, trabecular, and cribriform-like pseudoglandular structures. BSCCE demonstrates various histopathological and immunohistochemical features including a ductal and cribriform growth pattern.