myofibroblastic

Myofibroblastic is an adjective used in medical pathology to describe cells, tissues, or responses that involve myofibroblasts. Myofibroblasts are specialized fibroblast-like cells that exhibit features of both fibroblasts and smooth muscle cells. They are contractile and actively synthesize extracellular matrix, contributing to wound healing and tissue remodeling. The term is used to indicate the presence or predominance of myofibroblastic differentiation in a lesion or tissue sample.

Key characteristics of myofibroblastic cells include expression of alpha-smooth muscle actin (α-SMA) and vimentin, along with variable production of collagen and other matrix components. They form stress fibers, develop focal adhesions, and can contract the surrounding matrix, aiding in wound closure. In many contexts, myofibroblastic differentiation is a transient, reparative phase that resolves after tissue repair; persistent activity can contribute to fibrotic disease.

Origin and development of myofibroblasts are diverse. They can arise from resident fibroblasts under the influence of transforming growth factor-beta (TGF-β) and other cytokines, or from other cell types through epithelial-to-mesenchymal or endothelial-to-mesenchymal transitions, pericytes, or circulating fibrocytes. The myofibroblastic phenotype is thus a dynamic state linked to tissue injury, repair, and remodeling.

Clinically, a myofibroblastic pattern is noted in various settings, including wound healing, fibrotic diseases, and certain neoplasms. Inflammatory myofibroblastic tumor (IMT) is a notable example of a neoplasm showing myofibroblastic differentiation, sometimes associated with ALK gene rearrangements. Overall, the term emphasizes the presence of cells with dual fibroblastic and smooth muscle–like properties in health and disease.