Magnification endoscopy in esophageal squamous cell carcinoma: a review of the intrapapillary capillary loop classification.

Recent developments in image-enhancement technology have enabled clear visualization of the microvascular structure of the esophageal mucosa. In particular, intrapapillary capillary loops (IPCLs) are observed as brown loops on magnification endoscopy with narrow-band imaging (NBI). IPCLs demonstrate characteristic morphological changes according to the structural irregularity of esophageal epithelium and cancer infiltration, summarized in the IPCL classification. In this review, the process from the first endoscopic description of IPCLs to the eventual development of the IPCL classification is described and discussed, particularly focusing on early stage squamous cell carcinoma of the esophagus.

Microvascular architecture of early esophageal neoplasia.

Progress in magnifying endoscopy has allowed endoscopic atypia to be evaluated on the basis of the presence or the absence of microvascular hyperplasia in a tumor. We focused our attention on intra-epithelial papillary capillary loops (IPCLs) and studied 20 cases of esophageal neoplasia (IPCL type III, 10 cases; IPCL type IV, 10 cases) and 99 vessels (IPCL type III, 24 vessels; IPCL type IV, 75 vessels). We evaluated the histopathological findings and measured vessel caliber, distance from the basement membrane, distance between blood vessels and thickness of the epithelium. According to the Vienna classification, the histological findings in the 10 patients with IPCL type III lesions were classified as category 1 (negative for neoplasia/dysplasia) in 8 patients and category 3 (non-invasive low grade neoplasia) in 2 patients. The histological findings in the 10 patients with IPCL type IV lesions were classified as category 1 in 1 patient, category 3 in 4 patients and category 4 (non-invasive high grade neoplasia) in 5 patients. The vessel caliber of IPCL type IV lesions (mean, 5.9 ± 2.7 µm) was significantly larger than that of IPCL type III lesions (mean, 4.8 ± 1.5 µm) (P=0.013). The distance from the basement membrane of IPCL type IV lesions (mean, 99.9 ± 34.4 µm) was significantly greater than that of IPCL type III lesions (mean, 58.0 ± 36.2 µm) (P=1.52562E-06). The distance between blood vessels and the thickness of the epithelium did not differ significantly between IPCL type III and IPCL type IV lesions. Our results revealed that changes in vessels of IPCL type IV lesions involve two factors: increased vessel caliber and prolongation of IPCLs toward the surface. These vascular changes appear to be associated with increased atypia of blood vessels.

Endoscopic mucosal resection and endoscopic submucosal dissection for esophageal dysplasia and carcinoma.

Advanced cancer in the esophagus is a serious and fatal disease that invades locally to deeper layers of the esophageal wall with significant risk of nodal metastasis and invasion of adjacent organs. One reliable method of avoiding this is to detect lesions at an early stage of esophageal cancer and then to resect them locally. A major advantage of endoscopic local resection is to recover a specimen for histopathologic analysis, which helps to make a clinical decision for further therapy. Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have already been established as the techniques of endoscopic local resection. EMR includes strip-off biopsy, double-channel techniques, cap technique, EMR using a ligating device, and so on. ESD is a newly developed technique in which submucosal dissection is carried out using an electrocautery knife to acquire a single-piece specimen.

[NBI magnifying endoscopic classification using crystal violet staining].

NBI magnifying imaging with crystal violet (CV-NBI magnifying imaging) makes recognition of micro-vascular pattern and grandular structure in the gastric mucosa better. NBI image emphasizes micro-vascular structure in mucosal surface. Magnification endoscopy with crystal violet staining delineates surface grandular structure better than without it. Crystal violet stained epithelium is clearly observed as cobalt green with NBI imaging. In the classification of CV-NBI magnification findings, 71% of differentiated type lesion was classified into ILL (intralobular loop pattern), and the rest (29%) was diagnosed as FNP (fine network pattern) which was originally advocated by Nakayoshi, et al. ILL is the new category of magnifying endoscopy. ILL corresponded mainly to differentiated-type adenocarcinoma, but it also includes undifferentiated-type adenocarcinoma. Corkscrew pattern is corresponding well to undifferentiated-type adnocarcinoma (Nakayoshi, et al). CV-NBI magnifying classification is considered to be related to tissue characterization in gastric cancer.