A 65-year-old woman has had several months of progressive fatigue, diminished appetite, and unintentional weight loss. The patient has no chronic medical conditions. She has not received medical care in many years and has not had recommended cancer screening. The patient suddenly dies while undergoing evaluation. Autopsy reveals abnormal liver findings, as shown in the exhibit below. Microscopic evaluation of the lesions reveals neoplastic cells. Which of the following is the most likely cause of this patient's liver lesions?

Question

A 65-year-old woman has had several months of progressive fatigue, diminished appetite, and unintentional weight loss.  The patient has no chronic medical conditions.  She has not received medical care in many years and has not had recommended cancer screening.  The patient suddenly dies while undergoing evaluation.  Autopsy reveals abnormal liver findings, as shown in the exhibit below.  Microscopic evaluation of the lesions reveals neoplastic cells.  Which of the following is the most likely cause of this patient's liver lesions?

Quizplus · Accepted Answer

11ec160b_393d_6a09_9249_7904355711a0_MD0001_00 Liver neoplasms are most often due to metastases from distant tumors rather than primary liver cancer (eg, hepatocellular carcinoma). Metastatic disease to the liver is particularly likely when multiple tumors are present (as seen in this case) and there is no history of underlying hepatic disease such as alcohol-induced cirrhosis or hepatitis C. The liver is vulnerable to the metastatic spread of cancer due to the following anatomic considerations: The presence of fenestrated hepatic sinusoidal epithelium, which allows tumor cells to easily pass from the bloodstream through to the parenchyma. Dual blood supply from the portal and systemic circulation, which increases the likelihood of circulating tumor cells depositing in the liver. The most common cause of liver metastases is colorectal cancer, which spreads directly from the colon or superior rectum through the portal venous system to the liver. This patient, who has not received recommended cancer screening (eg, colonoscopy), likely developed hepatic metastases from colorectal cancer. Gastric and pancreatic cancers also frequently spread through the portal system to the liver. (Choice A) Lymphatic spread of tumor cells is a common mechanism of metastases, but it is not the primary source of most metastatic liver lesions. (Choice B) Tumors (eg, breast, lung, melanoma) can spread to the liver through the systemic circulation via the hepatic artery (rather than the portal circulation). The hepatic vein drains out of the liver; it does not bring blood into the liver. (Choice D) Primary hepatic cancer is thirtyfold less common than metastatic disease. Most primary lesions are solitary tumors and arise in individuals with underlying liver disease. This patient, who did not have recommended cancer screening (eg, colonoscopy) and has multiple liver tumors, most likely has metastatic disease. (Choice E) Although gastrointestinal cancers can spread to the peritoneum and then invade the liver, this is much less common than hematogenous dissemination through the portal system. Metastasis through the peritoneal space most commonly occurs with ovarian cancer and gastric (Krukenberg) tumors. Educational objective: Most hepatic neoplasms are due to metastatic disease from a distant site. Colorectal cancer is the most common cause of hepatic metastases due to direct blood flow from the colon (and superior rectum) to the liver via the portal venous circulation.

A 65-Year-Old Woman Has Had Several Months of Progressive Fatigue