AN UNUSUAL CASE OF TUMOR THROMBUS IN THE INFERIOR VENA CAVA
A case report
E. RADECKA1, E. BREKKAN2, C. JUHLIN3, L. NILSSON4, A. SUNDIN1 and A. MAGNUSSON1 Departments of 1Radiology, 2Urology, 3Surgery and 4Thoracic Surgery, University Hospital, Uppsala, Sweden.
Abstract
Adrenal cortical carcinoma (ACC) is a rare malignancy. Patients present either with a functional tumor or secondary to mass effect. In non-functioning tumors, the tumor size often exceeds 5 cm by the time of diagnosis, and tumor thrombus can occur.
We report on a case of a small non-functioning ACC causing a large tumor thrombus in the inferior vena cava.
Key words: Adrenal cortical carcin- oma; tumor thrombus; CT; PET.
Correspondence: Eva Radecka, Department of Radiology, Uppsala University Hospital, SE-751 85 Uppsala, Sweden. FAX +46 128 557279. E-mail: eva.radecka@rtg.uas.lul.se
Accepted for publication 18 November 2002.
Adrenal cortical carcinoma (ACC) is a rare neo- plasm with an incidence of 2 cases per million in a population. ACC is similar to renal cell carcinoma, Wilms’ tumor and testicular cancer in its ability to develop venous tumor thrombus, which occurs in 25-35% of cases with ACC (3).
Forty percent of ACC are hormonally inactive, giv- ing symptoms such as pain, weight loss and malaise.
The diagnosis of non-functional tumors is often made when the tumor is larger than 5 cm (2). Involve- ment of the inferior vena cava (IVC) by ACC is rare (1), and the adrenal tumor tends to be large, with a mean tumor size of 10.1 ± 5.6cm (4).
Case Report
A 60-year-old man presented with dyspnea. Chest radiography showed a minor opacity in the right lower lung lobe, interpreted as status post pneumonia.
One month later, the symptoms worsened with vague abdominal pain and bilateral leg edema. Blood samples showed raised transaminases. Echocardiography demonstrated a thrombus in the cranial part of the IVC. CT showed a thrombus in the IVC from the level of the renal veins extend- ing up to the level of the right atrium.
The following diagnostic alternatives were con- sidered: coagulation disorder, anomalous IVC or malignancy.
US-guided fine-needle aspiration biopsy of the caval thrombus showed neoplastic cells, indicating renal cell carcinoma. However, no renal tumor was shown on CT.
Repeated CT with thin slices and multiplanar reconstructions revealed that the left adrenal gland was slightly enlarged (2 cm), and with calcifications (Fig. a). A thrombus involved the left adrenal vein, the cranial part of the left renal vein extending to the IVC and into the right atrium (Figs b-d). Contrast
TUMOR THROMBUS IN THE INFERIOR VENA CAVA
a
b
d
e
~
c
enhancement of the thrombus of the IVC indicated viable tissue.
Positron emission tomography (PET) using 18 F fluorodeoxyglucose (FDG) was then performed. FDG is a glucose analog which is accumulated in malignant tumors, especially in those with a high metabolism. One hour after an i.v. injection of 535 MBq FDG the patient’s thorax and abdomen were examined in a Siemens ECAT PET scanner. The collected data were corrected for scatter and attenuation and an iterative image reconstruction was done. The images were displayed in the axial, coronal and sagittal planes and evaluated for patho- logical FDG deposits.
A high FDG uptake was found corresponding to the IVC consistent with a malignant tumor. The FDG accumulation was seen to reach cranially up to the right atrium and caudally in a curve-like manner to the left over the midline, ending in a small rounded lesion (Fig. e).
At surgery, left adrenalectomy, resection of the renal vein and thrombectomy in the right atrium, and IVC were performed. Extracorporeal circula- tion was used and the tumor thrombus was extir- pated under circulatory arrest in deep hypothermia with selective cerebral perfusion. The postoperative course was uneventful. Histopathology of the tissue samples from the left adrenal gland showed adrenal cortical carcinoma.
Discussion
Involvement of the IVC by ACC is rare and these patients usually present with large tumors. The majority of these tumors spread via intra- luminal extension due to the barrier effect of the intimal layer of the IVC. In 52% of IVC tumor cases the thrombus reaches the level of the right atrium (1).
CT and MR are the standard techniques for evaluation of tumor size and staging purposes. Ultrasound, CT, MR and cavography are recom- mended to evaluate IVC tumor thrombus. 18-FDG PET further established the diagnosis in the present case.
This unusual case illustrates the ability of small adrenal carcinoma to produce a large tumor thrombus.
REFERENCES
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