A 61-year-old woman has a follow-up evaluation for the incidental discovery of several hypodense lesions in both lobes of her liver and a 2.5-cm mesenteric mass during CT imaging for nephrolithiasis. She has fully recovered from the nephrolithiasis and now feels entirely well. She does not have abdominal pain, a change in either appetite or bowel habits, hot flushes, or facial flushing. She takes no medications.
On physical examination, vital signs and the remainder of the examination are normal.
Complete blood count and liver chemistry test results are normal.
A needle biopsy of an accessible liver lesion shows a well-differentiated low-grade neuroendocrine tumor, with a low rate of mitotic figures.
Which of the following is the most appropriate management?
A. Begin hormonal therapy with a somatostatin analogue
B. Hepatic artery embolization
C. No immediate intervention; repeat CT scan in 3 months
D. Surgery to remove primary tumor
E. Systemic chemotherapy
MKSAP Answer and Critique
The correct answer is C. No immediate intervention; repeat CT scan in 3 months. This content is available to MKSAP 18 subscribers as Question 115 in the Hematology and Oncology section. More information about pre-ordering MKSAP 19 is available online.
The most appropriate management for this patient is to not intervene now and repeat the CT scan in 3 months. Neuroendocrine tumors can arise from the endocrine cells of the pancreas or neuroendocrine cells of the aerodigestive tract. These two entities look and behave similarly; however, several anticancer agents that show activity against pancreatic neuroendocrine tumors show little or no activity against aerodigestive tumors. This patient is asymptomatic with an incidental finding of a well-differentiated, low-grade, small-bowel gastrointestinal neuroendocrine tumor (previously known as carcinoid) with multiple small metastases to the liver. The liver is overwhelmingly the most common site of metastasis, and diagnosis is often established through an incidental finding of hepatomegaly or abnormal findings on an imaging study. Such tumors are often asymptomatic and indolent, and asymptomatic patients may do well, with minimal growth and no symptoms for years, even with metastatic disease. As such, there is no urgency to intervene. Follow-up examination and imaging at approximately 3 months is appropriate. Although perhaps 25% of metastatic gastrointestinal neuroendocrine tumors will elaborate serotonin, a hormone causing diarrhea or facial flushing (carcinoid syndrome), most patients have a hormonally nonfunctional tumor and thus do not require treatment for these symptoms. In patients whose disease appears stable on the 3-month CT scan, further monitoring with serial imaging at 3- to 6-month intervals is appropriate.
Hepatic arterial embolization may be helpful in shrinking liver metastases or reducing hormonal output from functional tumors and may be considered in a patient with progressive or symptomatic disease.
Obstruction of the bowel from a well-differentiated neuroendocrine primary tumor is very uncommon, so prophylactic surgery to remove the primary bowel tumor in an asymptomatic patient with metastases is not indicated.
Chemotherapy for gastrointestinal neuroendocrine tumors is of limited utility in asymptomatic patients with small volume disease that has not been demonstrated to be progressive. In these patients, the toxicities of treatment outweigh the benefit.
- Well-differentiated, low-grade, metastatic gastrointestinal neuroendocrine tumors are often indolent and asymptomatic and do not require immediate treatment.