|Year : 2017 | Volume
| Issue : 3 | Page : 221-223
18F-Fluorodeoxyglucose positron emission tomography-computed tomography scan finding of portal venous tumor thrombus in a case of primary gastric malignancy
Jayanta Das1, Soumendranath Ray1, Sudipta Nag1, Ashish Kumar2, Sumit Mukhopadhyay1
1 Tata Medical Center, Kolkata, West Bengal, India
2 Department of Oncosurgery, Tata Main Hospital, Jamshedpur, Jharkhand, India
|Date of Web Publication||13-Jun-2017|
Tata Medical Center, Kolkata, West Bengal
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Intraluminal portal venous tumor thrombus is an infrequent association with primary gastric malignancy. Ultrasonography features such as low pulsatile flow within the thrombus, expansion of vein, and enhancement of thrombus are nonspecific findings for diagnosis. 18F-fluorodeoxyglucose positron emission tomography-computed tomography scan can differentiate between the benign and malignant thrombus as well as it helps proper metastatic work up. We report such a case.
Keywords: Gastric adenocarcinoma, positron emission tomography, portal vein, thrombus
|How to cite this article:|
Das J, Ray S, Nag S, Kumar A, Mukhopadhyay S. 18F-Fluorodeoxyglucose positron emission tomography-computed tomography scan finding of portal venous tumor thrombus in a case of primary gastric malignancy. Indian J Nucl Med 2017;32:221-3
|How to cite this URL:|
Das J, Ray S, Nag S, Kumar A, Mukhopadhyay S. 18F-Fluorodeoxyglucose positron emission tomography-computed tomography scan finding of portal venous tumor thrombus in a case of primary gastric malignancy. Indian J Nucl Med [serial online] 2017 [cited 2017 Sep 26];32:221-3. Available from: http://www.ijnm.in/text.asp?2017/32/3/221/207882
| Introduction|| |
Intraluminal portal venous tumor thrombus (PTT) is an infrequent finding in 18 F-fluorodeoxyglucose positron emission tomography-computed tomography (18 F-FDG PET-CT) scan. It is most frequently associated with hepatocellular carcinoma (HCC). Pancreatic and other gastrointestinal (GI) cancers are among the rare causes of PTT. We report such an uncommon case of primary gastric adenocarcinoma presenting with massive tumor thrombus in the portal vein as a solitary metastatic lesion. In this article, we also discuss PET-CT features of malignant tumor thrombus with some literature review.
| Case Report|| |
A 64-year-old patient was presented with black stool indicating upper GI bleeding. Endoscopy revealed Grade I esophageal varices, features of erosive gastritis, and nodular ulceration of the wall of the gastric fundus. Ultrasonography (USG) upper abdomen showed an echogenic filling defect in the expanded portal vein with flow void [Figure 1]. Gastric biopsy of the fundal ulcer confirmed moderately differentiated adenocarcinoma. After initial conservative management, he was referred for staging PET-CT scan.
|Figure 1: (a) Axial section ultrasonography image at the level of portal vein bifurcation shows echogenic filling defect and enlargement of the portal vein (white arrow). No blood flow was detected in Doppler study. (b) Splenic vein shows normal course, caliber and flow pattern|
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A whole body contrast-enhanced PET-CT scan along with a triple phase CT scan of upper abdomen was performed. The scan showed a polypoidal mural lesion with markedly increased metabolic activity in the gastric fundus along the greater curvature which was consistent with primary malignant pathology. In addition, patient had a large intraluminal filling defect in the portal venous system. The thrombus showed markedly increased and homogenous metabolic activity with maximum standardized uptake value (SUVmax) 28.32. The lesion was in the main portal vein just distal to its formation. It extended along the intrahepatic portal radical in a branching pattern in almost all segments in both lobes of the liver. The main portal vein as well as intrahepatic portal radials were dilated. The intraluminal filling defect showed heterogenous contrast enhancement, better appreciated in arterial phase [Figure 2]. The venous phase of the scan also demonstrated multiple gastro-esophageal varices and portal cavernoma. These imaging features of an expansile enhancing hypermetabolic portal venous filling defect in a known case of primary gastric carcinoma led to the diagnosis of metastatic PTT [Figure 3].
|Figure 2: Arterial phase contrast enhance computed tomography scan at the level of portal vein shows early enhancement of the portal venous tumor thrombus (black arrow). A polypoidal mural lesion is seen at the fundus of the stomach (white arrow)|
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|Figure 3: (a) Maximum intensity projection image of whole body PET-CT shows FDG avid primary gastric tumor (single arrow). FDG avid filling defect in portal venous system in branching pattern (double arrow) indicates malignant portal venous tumor thrombus. (b) Contrast-enhanced CT scan in venous phase shows portal venous system at bifurcation is filled up with thrombus. (c) Fused PET-CT image in axial section through the same plane shows branching thrombus with intrahepatic extension in both lobes of the liver. Both the thrombus as well as gastric mural lesion show high grade metabolic activity confirming the tumor thrombus in portal vein. FDG: Fluorodeoxyglucose, PET-CT: Positron emission tomography-computed tomography|
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The rest of the whole body scan in our case did not show any other evidence of metastatic involvement.
| Discussion|| |
The documented incidence of malignant PTT in gastric adenocarcinoma is 1.6%. Hepatoid variety of adenocarcinoma of the stomach is more frequently associated with PTT. Many of these patients also have increased alpha-fetoprotein (AFP). In our case, the AFP was normal (6 ng/ml), and histopathology revealed papillary adenocarcinoma. Malignant PTT associated with neuroendocrine tumor of the stomach has also been reported. The conventional radiological modalities can inconsistently differentiate malignant PTT from benign thrombus. Pulsatile intra-thrombus blood flow detected in Doppler USG was described as highly specific for malignant thrombus, but the feature lacks the acceptable sensitivity. Moreover, pulsatile flow in PTT was predicted to be frequently associated with HCC but not with gastric primary, former being more vascular in nature. Enlargement of the portal vein, thrombus enhancement, and neovascularity of the thrombus have been independently considered as features of malignant thrombus. However, retrospective analysis of CT scan of patients with PTT and gastric adenocarcinoma by Araki et al. failed to establish any differentiation between malignant and benign thrombus, although celiac angiography showed thrombus hypervascularity in one patient. The role of the PET-CT scan in differentiation between malignant and benign thrombus has been described by Sharma et al. Significantly, high SUV value has been demonstrated in the malignant thrombus in their observation. Although there was overlap between benign and malignant thrombus, they proposed SUVmax 3.63 as cut-off value with 72% sensitivity and 90% specificity. In our case, enhancing portal venous thrombus with dilated portal radical and hypermetabolic activity in a known case of gastric adenocarcinoma indicates malignant PTT as the most likely etiology. The role of the PET-CT scan in detection of asymptomatic tumor thrombus has also been mentioned in details by Lai et al.
| Conclusion|| |
Although HCC is most common, it is not the only malignancy causing malignant PTT. Gastric adenocarcinoma rarely may be associated with malignant PTT. As in our case, PET-CT scan can differentiate between the benign and malignant nature of intravascular thrombus in cases of gastric malignancy and can serve as one-stop investigation for the evaluation of thrombus as well as metastatic work up. The hypermetabolic activity of tumor thrombus detected by PET-CT scan has an incremental value over the conventional imaging (USG/CT/magnetic resonance imaging) in the detection of malignant thrombus.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]