Carcinoma tuyến Bronchiolo phế nang phổi có một mô hình điển hình "lepidic" tăng trưởng các tế bào khối u thay thế pneumocytes bình thường, do đó giữ được các thành phần đệm của thành phế nang và coopting mạch máu mao mạch. Cấu trúc của nhu mô phổi vẫn còn nguyên vẹn, | 944 Part III Pathology Figure 2 Replacement growth pattern in a liver metastasis of a breast adenocarcinoma. The tumor cells left are replacing the hepatocytes in the liver plates right thereby coopting the sinusoidal blood vessels. There is close apposition of tumor cells and hepatocytes at the tumor-liver interface arrows without induction of inflammation or fibrosis. metastases with a replacement growth pattern expressed the hypoxia marker CA IX or had fibrin depositions at the tumor-liver interface Table II . Probably the well-described mechanisms of invasive tumor growth such as fibroblast-myofibroblast transdifferentiation TGFb pathways proinflammatory signaling hyaluronic acid action and hypoxia-responsive gene activation are not involved. The search for gene sets that are responsible for the phenotype of nonangiogenesis-dependent colonization of a distant site is ongoing. Selective induction of apoptosis in hepatocytes at the interface by tumor cells might be one of the mechanisms of growth of blood-vessel-coopting metastases. The other growth patterns in the liver were characterized by destruction of the architecture of the liver parenchyma and were associated with desmoplasia and new blood vessel formation. The metastases were desmoplastic growth pattern or were not pushing growth pattern surrounded by a fibrotic capsule. The consequences of this heterogeneity of human liver metastases are the limited value of model systems that selectively reproduce the well-studied angiogenesis-dependent growth of metastases and the difficulties in analyzing the results of clinical trials applying biomodulatory drugs. Imaging of the vascular flow and leakage by contrast-enhanced CT or MR might be helpful in selecting patients with angiogenic versus nonangiogenic liver metastases. The existence of different growth patterns also stresses the superior value of the endothelial cell proliferation ECP fraction for angiogenesis quantification compared to microvessel density 1
