18F-fluorodeoxyglucose positron emission tomography-computed tomography finding of left gonadal vein thrombosis in a case of renal cell carcinoma.

Tumor thrombus from renal cell carcinoma is commonly reported in renal vein and inferior vena cava with a few reports of gonadal vein involvement. Here, we report a case of an elderly female who underwent fluorodeoxyglucose (FDG) positron emission tomography-computed tomography scan for initial staging of left renal cell carcinoma. Along with an FDG avid left renal mass lesion, scan also revealed FDG avid tumor thrombus in the entire length of the left gonadal vein.

An 80-year-old female presented with complaint of hematuria. Contrast-enhanced computed tomography (CECT) abdomen revealed the left renal mass with renal vein and infra-diaphragmatic inferior vena cava (IVC) thrombosis. Fluorodeoxyglucose (FDG) positron emission tomography-CT (PET-CT) scan was done for staging workup. Scan findings revealed an FDG avid left renal mass lesion [Figure 1]. FDG avid tumor thrombus was seen along the entire length of the left renal vein, extending up to the IVC. FDG avid tumor thrombus was also seen in the distended left gonadal vein, extending along its entire length [Figure 2], located anteromedial to the left ureter [Figure 3]. FDG avid multiple lytic destructive skeletal lesions, left adrenal nodule, and right pleural thickenings were also seen along with non-FDG avid liver lesions and bilateral lung nodules.

Figure 1

18F fluorodeoxyglucose positron emission tomography maximum intensity projection image (a) showing focal areas of abnormal fluorodeoxyglucose uptake in left renal fossa region, abdomen, and mediastinum. Axial contrast-enhanced computed tomography (b) and positron emission tomography-computed tomography (c) images showing fluorodeoxyglucose avid left renal mass replacing the entire left renal parenchyma (white arrow). Fluorodeoxyglucose avid enhancing tumor thrombus is seen in the left renal vein along its entire length and extending up to the inferior vena cava (red-notched arrow). Fluorodeoxyglucose avid enhancing tumor thrombus is also seen in the left gonadal vein (arrowhead)

Figure 2

Sagittal contrast-enhanced computed tomography (a) and positron emission tomography-computed tomography (b) images showing fluorodeoxyglucose avid enhancing tumor thrombus along the entire length of the left gonadal vein. Coronal contrast-enhanced computed tomography (c) and positron emission tomography-computed tomography (d) images showing the fluorodeoxyglucose avid left gonadal vein tumor thrombus extending up to the left ovary (arrow)

Figure 3

Axial contrast-enhanced computed tomography (a and c) and positron emission tomography-computed tomography (b and d) sections at 10 mm interval showing fluorodeoxyglucose avid enhancing tumor thrombus in the left gonadal vein (white-notched arrow) which is located anteromedial to the left ureter (blue arrow)

The incidence of venous tumor formation has been reported to occur in 4–10% of patients with renal cell carcinoma.[1] A few cases of involvement of gonadal vein have also been reported.[23] A tumor thrombus appears as an enhancing endoluminal filling defect on CECT scan[4] with focal/linear increased FDG uptake on FDG-PET-CT scan.[5] The sensitivity and specificity of FDG uptake in the diagnosis of tumor thrombus increase with increase in FDG uptake.[6]

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