Microvascular Architecture in Esophageal Cancer Observed by Stereomicroscopy

Background Observation of microvascular structures using magnifying endoscopy is useful for distinguishing between tumor and non-tumor areas, as well as for diagnosing wall invasion depth in esophageal cancer. However, while magnifying endoscopy findings are often compared with histological vascular structures, the detailed changes in microvascular structures associated with tumor growth remain unclear. Methods We studied esophageal superficial squamous cell carcinoma treated with ESD at our institution. Using a stereomicroscope, we observed the tumor surface and cut surface to evaluate the course, morphological changes of intra-papillary capillary loops (IPCLs), and their relationship with tumor nests. IPCL changes were classified based on the Esophageal Society magnifying endoscopy classification. Type B vessels were further subdivided into Type B1 with loop-like structures and Type B2 with fewer loops. Areas surrounded by Type B vessels, with few or no blood vessels, were defined as avascular areas (AVA). Results We observed 7 ESD specimens of esophageal cancer. Pathological depth included T1a-EP (1), T1a-LPM (5), and T1b-SM (1). In T1a-EP, Type B1 vessels were noted on the surface, with vessels connecting to the underlying mucosa. In T1a-LPM, AVA cases showed tumor nests surrounded by micro vessels with invasive growth, while non-AVA cases had disrupted papillary structures. In T1b-SM, Type B2 vessels were seen around areas of epithelial detachment. Cut surface showed unclear vessels beneath the epithelium and connections to submucosal vessels. Conclusion Observation of the cut surface using a stereomicroscope allowed for deep evaluation of vascular structures. Additionally, by positioning the cut surface in the area of interest, direct observation may help clarify the relationship between microvascular structures and tumor nests.