A 65-year-old man dies after a protracted battle with meta- static colon carcinoma. At autopsy, the liver is filled with multiple nodules of cancer, many of which display central necrosis (umbilication). Which of the following best explains the pathogenesis of tumor umbilication in this patient?
Angiogenesis is a requirement for the continued growth of cancers, whether primary or metastatic. In the absence of new vessels to supply the nutrients and remove waste products, malignant tumors do not grow larger than 1 to 2 mm in diameter. In general, causes of tumor cell death in situ include (1) programmed cell death (apoptosis); (2) inadequate blood supply, with consequent ischemia; (3) a paucity of nutrients; and (4) vulnerability to specific and nonspecific host defenses. The CT scan shows central necrosis (umbilication) in most of the metastatic tumor nodules. None of the other choices are likely causes of tumor necrosis.Diagnosis: Metastatic cancer
Biphasic tumor
Chronic inflammation
Granulomatous inflammation
Ischemia and infarction
Neoplasia