Pedunculated malignant colonic polyps with superficial invasion of the stalks

Tumor progression is a phenomenon where the pre-formed tumor acquires successive mutations to become clinically more aggressive and malignant. In the 1950s, Foulds first described the stepwise progression of cancer cells through successive stages.
Colon cancer is one of the best-documented examples of tumor progression. Early mutation in the APC gene in colon cells causes a small growth on the colon wall called a polyp. With time, this polyp grows into a benign, pre-cancerous tumor. Further...

Metastasis is the spread of cancer cells from the original site to distant locations in the body. Cancer cells can spread via blood vessels (hematogenous) as well as lymph vessels in the body.
Epithelial-to-Mesenchymal Transition
The epithelial-to-mesenchymal transition or EMT is a developmental process commonly observed in wound healing, embryogenesis, and cancer metastasis. EMT is induced by transforming growth factor-beta (TGF-β) or receptor tyrosine kinase (RTK) ligands, which further...

Invadosome is a broad category of cell surface structures with proteolytic activity that  degrades the extracellular matrix (ECM). Invadosomes are present in normal cell types, including macrophages, endothelial cells, and neurons, as well as tumor cells. Although the macrophage podosomes and tumor cell invadopodia are classified as invadosomes, they have different structures, molecular pathways, and functions. Podosomes are short structures that last for a few minutes. However, invadopodia can...

Diverticular disease involves the formation of diverticula—small sac-like outpouchings of the colonic wall—and their complications. It most commonly affects the sigmoid colon due to higher intraluminal pressure and structural vulnerability. It results from structural weakness and increased pressure in the colon, producing pseudodiverticula that may remain silent or progress to inflammation and serious complications.Structure of DiverticulaIn diverticulosis, these outpouchings are...

Appendicitis is an acute inflammatory condition of the vermiform appendix, most commonly caused by obstruction of its lumen. The appendix is a narrow, blind-ended pouch that extends from the cecum, making it particularly prone to obstruction. Causes include fecaliths, lymphoid hyperplasia (often after viral infections), parasites, tumors, or foreign bodies. This obstruction initiates a cascade of pathological changes.Luminal Obstruction and Early InflammationAfter obstruction, normal mucosal...