Correct answer to Q2 is: Liver metastasis from intestinal cancer
Discussion:
A hypoechoic halo, which is a hypoechoic rim in the periphery of a lesion, is a concerning feature of liver masses. It has been shown to be highly indicative of malignancy compared with lesions without halo (1). In this case, contrast-enhanced ultrasound was unavailable, but it might have revealed more lesions, and would probably have determined the malignant origin. As liver metastases most often originate from the colon, the colon was carefully inspected during the ultrasound examination, and this revealed intestinal wall thickening in the right lower quadrant. Based on these findings, a thoracic and abdominal CT scan and a colonoscopy were recommended.
The CT scan revealed a tumor in the terminal ileum. After the CT scan, a colonoscopy with biopsies from the terminal ileum was performed. The following histopathology determined the mass to be a neuroendocrine tumor (NET) with a Ki-67 proliferative index of 3%, meaning it was an intermediate-grade tumor (2). The currently recommended examinations for imaging of patients with NETs include a combination of molecular and morphologic imaging. Therefore, a Cu-DOTATATE-PET/CT (somatostatin analogue radiotracer) was performed to determine malignant spread (Image 6 and 7). The scan showed the tumor in the terminal ileum and several liver metastases, at least 20. Diffusion-weighted MRI has proven very sensitive for detection of liver metastases (3), and to determine the possibility of liver resection, it was also performed. Unfortunately, the MRI revealed multiple sub-centimeter metastases in all liver segments except segment 1, making them irresectable (Image 8).
This patient had a mid-gut NET with liver metastases, but she did not present with the typical carcinoid syndrome (i.e., flushing, diarrhea, tachycardia, or hypotension, bronchospasms, and right-sided heart failure), even though mid-gut NETs with metastases are among the most common tumors to cause the syndrome. However, only roughly 10% of patients with NETs experience typical carcinoid symptoms. It is more typical for these patients to present with weak and unspecific symptoms, and many small bowel NETs are found by coincidence (4,5). Among symptomatic patients with small bowel NETs, abdominal pain is one of the most common initial symptoms. In addition, intermittent obstruction occurs in approximately 25% of small bowel NETs. In this case, the patient’s symptoms with intermittent upper abdominal pain and vomiting could have been caused by intermittent bowel obstruction.
In conclusion, one should look carefully at the other intraabdominal organs and intestines when liver metastases are seen or suspected. In female patients an origin in the breasts should also be considered.
Conflicts of interest
“The authors declare no conflict of interest.”
References
- Wernecke, K.; Vassallo, P.; Bick, U.; Diederich, S.; Peters, P.E. The distinction between benign and malignant liver tumors on sonography: Value of a hypoechoic halo. Am. J. Roentgenol. 1992, 159, 1005–1009.
- Nagtegaal, I.D.; Odze, R.D.; Klimstra, D.; Paradis, V.; Rugge, M.; Schirmacher, P.; Washington, K.M.; Carneiro, F.; Cree, I.A. The 2019 WHO classification of tumours of the digestive system. Histopathology 2020, 76, 182–188.
- d’Assignies, G.; Fina, P.; Bruno, O.; Vullierme, M.P.; Tubach, F.; Paradis, V.; Sauvanet, A.; Ruszniewski, P.; Vilgrain, V. High sensitivity of diffusion-weighted mr imaging for the detection of liver metastases from neuroendocrine tumors : Comparison with t2-weighted and dynamic gadolinium-enhanced mr imaging. Radiology 2013, 268, 390–399.
- Kulke, M.H.; Mayer, R.J. Carcinoid tumors. N. Engl. J. Med. 1999, 340, 858–68.
- Cheung, V.T.F.; Khan, M.S. A guide to midgut neuroendocrine tumours (NETs) and carcinoid syndrome. Frontline Gastroenterol. 2015, 6, 264–269.
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