Infiltrierendes

Infiltrierendes is an adjective used in German to describe tissue, cells, or growth that invade and spread into surrounding structures. In pathology it refers to an invasive, poorly demarcated pattern where the lesion extends beyond its original bounds, rather than forming a clearly defined, encapsulated mass.

The term is commonly applied to tumors, especially carcinomas, that exhibit infiltrative growth. An example is infiltrierendes duktales Karzinom der Brust (invasive ductal carcinoma of the breast), where cancer cells penetrate the surrounding breast tissue and interact with the stromal compartment. In histological examination, infiltrierendes growth is characterized by tumor cells penetrating the basement membrane and extending into adjacent tissues, often accompanied by desmoplastic reaction and stromal remodeling.

Mechanisms underlying infiltrative behavior include loss of cell–cell adhesion (such as reduced E-cadherin expression), epithelial–mesenchymal transition, and the action of proteolytic enzymes like matrix metalloproteinases that break down extracellular matrix. These processes facilitate migration into surrounding tissue and potential spread to regional lymph nodes or distant sites.

Clinically, infiltration tends to indicate a more aggressive phenotype and can be associated with higher stage and worse prognosis compared with well-circumscribed lesions. Imaging and biopsy aim to assess the extent of infiltration to guide treatment decisions, including surgical planning and adjuvant therapy.

Beyond oncology, the term can also describe inflammatory or immune cell infiltration, where lymphocytes or other cells permeate tissues in response to infection or injury. In all uses, infiltrierendes conveys an active invasion into adjacent structures rather than mere expansion.