Pathology of Colorectal Cancer

Abstract

Background: Colorectal cancer (CRC) is a heterogeneous and multifactorial malignancy resulting from complex interactions between environmental exposures, lifestyle factors, chronic inflammation, and genetic susceptibility. It develops through progressive accumulation of molecular alterations that transform normal colonic epithelium into invasive carcinoma. Multiple carcinogenic pathways have been identified, including chromosomal instability, microsatellite instability, and CpG island methylator phenotype, each associated with distinct clinicopathological features. Histologically, CRC exhibits diverse subtypes and grades that influence tumor behavior, prognosis, and response to therapy. In addition, pathological features such as lymphovascular invasion and perineural invasion play a critical role in tumor progression and metastatic potential. Obstructed colorectal cancer represents a more aggressive clinical entity, often associated with advanced stage, unfavorable pathological characteristics, and poorer outcomes. Understanding the pathological and molecular mechanisms of CRC is essential for accurate diagnosis, prognostic assessment, and guiding therapeutic strategies.