Imaging of colorectal adenomas with pseudoinvasion and malignant polyps using two-photon excitation microscopy

Abstract Purpose Even though the incidence and mortality rates of colorectal cancer varies widely, it remains one of the most frequently diagnosed cancers in the world. Efforts are made to prevent the development of colorectal cancer by detecting precursor lesions during colonoscopy. The diagnosis of endoscopically resected polyps is based on hematoxylin and eosin staining examination. Difficult cases, such as adenomatous polyps with epithelial misplacement could benefit from certain ad-ditional diagnostic methods. Procedures The objective of this paper is to highlight stromal changes that appear in malignant polyps and polyps with pseudoinvasion, using two-photon excitation microscopy (TPEM), a technique largely used in the medical field in recent years. Results Examination of TPEM images revealed a different distribution and density of collagen fibers at the front of invasion, in malignant polyps, compared to the area of pseudoinvasion. Conclusions TPEM could be useful in distinguishing true invasion in malignant polyps from pseudoinvasion, based on a better visualization of the local stromal changes.