Esophageal early basaloid squamous carcinoma with unusual narrowband imaging magnified endoscopy findings

Figure 1 White-light endoscopy revealed a reddish depressed lesion 5 mm in diameter having a subepithelial tumor-like prominence (A), the depressed area was observed as a brownish area by narrowband imaging (B).

Figure 2 Narrowband imaging magnified endoscopy revealed irregular loop-shaped microvessels (without arrow) coexisting with irregularly branched thick non-looped vessels (arrows).

Figure 3 Irregularity or thinning of the third of a total of five layers, which corresponded to the submucosal layer, was not obvious in endoscopic ultrasonography.

Figure 4 Iodine staining revealed a pale brown lesion.

Figure 5 Hyperchromatic tumor cells. A: Histologically, basal cell-like hyperchromatic tumor cells proliferated mainly in the lamina propria; B: Immunostaining with desmin suggested that the tumor invaded the submucosa at a depth of 320 μm; C: The tumor cells formed solid nests and microcystic structures; D: The microcystic structures contained an Alcian blue-positive mucoid matrix; E: Immunostaining for α-SMA was negative; F: Thin vessels (arrowheads) were observed in the intra-epithelial papilla, and thick vessels (arrows) were observed around the solid nests just below the epithelium.