CT appearance of calcified tumor thrombus in the inferior vena cava

Abstract

Abstract.We report the unusual occurrence of calcified tumor thrombus in the inferior vena cava (IVC) in a patient with renal cell carcinoma diagnosed by computed tomography (CT).Key words: Renal cell carcinoma, calcified tumor thrombus--Computed tomography.Extension of tumor thrombus into the inferior vena cava (IVC) is a well-known complication of renal cell carcinoma. The thrombi appear on computed tomography (CT) as solid endoluminal masses with the same attenuation as the primary renal tumor. We report the unusual occurrence of calcified tumor thrombus in the IVC in a patient with renal cell carcinoma who also had calcification of the primary tumor and metastatic lymph nodes. To our knowledge, this is the first report of calcified tumor thrombus in the IVC from renal cell carcinoma. Case ReportA 43-year-old woman was admitted to our institution for treatment of metastatic renal cell carcinoma. She was well until 6 months prior to admission when she noted a left supraclavicular mass. Biopsy of the mass demonstrated adenocarcinoma. CT revealed a right renal neoplasm with metastatic disease in the chest and abdomen. She initially refused treatment.On physical examination there was a 12 x 6 cm fight flank mass, a 2 cm left supraclavicular mass, and bilaterallower extremity edema. Laboratory evaluation was remarkable for a hemoglobin of 9.5 g/ dl, lactate dehydrogenase of 407 IU, and gross blood in the urine.CT of the chest and abdomen demonstrated a partially calcified right renal mass replacing most of the kidney. There was calcified tumor thrombus extending into the right renal vein and proximally (Fig. 1A-C). Calcified lymphadenopathy was noted in the retroperitoneum, mediastinum, and hila (Fig. 1D). Multiple lung metastases were present and there were extensive retroperitoneal and subcutaneous venous collaterals.She was treated with interleukin and no additional imaging procedures were obtained. DiscussionThe CT features of renal cell carcinoma have been thoroughly described. Calcification within the primary tumor and venous extension of tumor are not unusual [1][2][3][4]. To our knowledge, however, venous extension of calcified tumor thrombus has not been described. In a series of 215 patients with renal cell carcinoma, discreet calcification was noted in the primary tumor in 24 (31%) [1]. In this series, there were no cases of calcified tumor thrombus extending into the renal vein or IVC. In another series, which reported the results of CT staging of 100 renal cell carcinomas, no cases of calcified tumor thrombus were described in the 18 patients with venous extension [2].Although calcified tumor thrombus in the renal vein and IVC in patients with renal cell carcinoma is rare, it could be important for persons doing abdominal imaging to be aware of this entity. The diagnosis on CT is straightforward due to the high attenuation of calcium. On ultrasound or magnetic resonance imaging (MRI), however, the presence of calcified tumor thrombus could result in confusion if this possibility was not considered. Ca...