CaroVascular

Cardiovasc Intervent Radiol (198 l) 4 : 15 l-157

and Interventional Springer-Verlag 1981

CT Diagnosis of Venous Pseudotumors in the Chest and Abdomen M i c h a e l K. W o l v e r s o n , B h a r g a v i Patel, M u r a l i S u n d a r a m , a n d E l i z a b e t h H e i b e r g Department of Radiology, St. Louis University School of Medicine. St. Louis, Missouri. USA

Abstract. A p p e a r a n c e s s i m u l a t i n g n e o p l a s t i c m a s s e s w e r e f o u n d in five p a t i e n t s u n d e r g o i n g c o m p u t e d tom o g r a p h i c (CT) s c a n n i n g o f the chest a n d a b d o m e n f o r a v a r i e t y o f i n d i c a t i o n s . In e a c h case the a p p e a r a n c e w a s s h o w n to be d u e to d i l a t e d c o l l a t e r a l v e n o u s c h a n n e l s in a s s o c i a t i o n w i t h p o r t a l h y p e r t e n s i o n o r interruption of the inferior vena cava. The vascular o r i g i n o f t h e m a s s e s w a s c o n f i r m e d by C T s c a n n i n g during intravenous bolus injection of contrast. Angiog r a p h i c c o n f i r m a t i o n was o b t a i n e d in t h r e e subjects. E n l a r g e d c o l l a t e r a l v e i n s s h o u l d be c o n s i d e r e d in the differential diagnosis of appearances suggesting m e d i a s t i n a l o r a b d o m i n a l l y m p h a d e n o p a t h y at C T scanning.

Key words: C o m p u t e d t o m o g r a p h y

Collaterals, veno u s - p s e u d o t u m o r - V e n a e cave, o c c l u s i o n - p o r t a l vein, h y p e r t e n s i o n

On plain chest radiography, azygous and hemiazyg o u s v e i n s m a y p r e s e n t as p a r a v e r t e b r a l m a s s e s w h e n d i l a t e d , u s u a l l y d u e to o c c l u s i o n o r i n t e r r u p t i o n o f the superior or inferior vena cava but occasionally to p o r t a l h y p e r t e n s i o n [1 5]. In t h e a b d o m e n c o l l a t e r al v e i n s in a s s o c i a t i o n w i t h p o r t a l h y p e r t e n s i o n m a y be v i s u a l i z e d as p s e u d o t u m o r s o f the g a s t r o i n t e s t i n a l t r a c t o n b a r i u m studies [6-8]. T h e c o u n t e r p a r t to this d i a g n o s t i c p r o b l e m in c o m p u t e d t o m o g r a p h y ( C T ) s c a n n i n g is the r e s e m b l a n c e t h a t i m a g e s o f a n o m a l o u s or c o l l a t e r a l veins m a y h a v e to l y m p h n o d e e n l a r g e m e n t [10-13]. F i v e cases d e m o n s t r a t i n g v e n o u s p s e u d o t u m o r s o n C T scans a r e i n c l u d e d in this r e p o r t . T h e p o t e n t i a l l y ser i o u s c o n s e q u e n c e o f c o n f u s i o n w i t h n e o p l a s m is e m -

Address reprint request to: M.K. Wolverson, M.D., Department of Radiology, St. Louis University Hospital, 1325 South Grand Blvd., St. Louis, MO 63104, USA

p h a s i z e d as is the n e e d for s c a n n i n g d u r i n g i n t r a v e n o u s b o l u s i n j e c t i o n o f c o n t r a s t to r e s o l v e d i a g n o s t i c difficulties.

Subjects and Methods During the past six months we have diagnosed venous collateral pseudotumors in five patients, a 10-year-old child and four adults, three men and one woman, ranging in age from 21 to 59 years. The indication for examination was suspected intra-abdominal neoplasm in two patients (Cases 1 and 2) and for follow-up of a known islet cell tumor of the pancreas in another (Case 5). The fourth adult was being investigated for jaundice (Case 3) and the child (Case 4) for long-standing liver enlargement. The CT body scans were performed with a Siemens Somatom using a scan time of 5 seconds and a section thickness of 8 ram. The upper abdomen and lower thorax were first scanned at 1.6 cm intervals after administration of oral contrast material. At the initial CT studies performed in Cases 1, 2, and 5, scanning was repeated following an intravenous bolus injection of 70-100 ml of 60% meglumine iothalamate. The contrast was delivered at a rate of 3 ml/sec via an antecubital vein using an 18-gauge needle. In these instances no particular attention was paid to timing of scans in relation to the injection at regions of interest. Scanning at regions of interest during bolus injection of contrast was undertaken at some stage of investigation in all five subjects. It was performed at the initial CT study in Cases 3 and 4 and at a second CT study in Cases 1, 2, and 5. In these instances, the same bolus injection procedure was used. with the patient positioned at the slice level revealing the suspected pseudotumor(s) at the precontrast study. The first image was obtained when half the contrast had been injected. Then two or three additional images were obtained at t5-second intervals at the same level. This ensured that images were obtained showing dense opacification of the major veins and associated venous collaterals in the section of interest. Immediate viewing of each image as it was obtained, within the 15-second interval between scans (reconstruction time, 5 seconds), enabled immediately adjacent areas of interest to be scanned as rapidly as possible as soon as satisfactory vascular delineation had been demonstrated in the initial section of interest~ Since the rate of transit of contrast in an obstructed venous system is slow, it was thus possible to obtain several adjacent slices with dense vascular opacification. Arterial portography was performed in two subjects (Cases 2 and 4). Inferior vena cavography was performed in one subject (Case 4) and radionuclide venography in another (Case 1).

0174-1551/81/0004/0151/$01.40

152 Case 1

A 55-year-old m a n presented with a one-year history of pain and swelling of his right leg and groin. He was otherwise well and had not lost weight. There was no relevant previous medical history. Physical examination revealed minimal pitting edema and swelling of the right leg and calf. There were dilated subcutaneous veins at the right groin and on the anterior abdominal wall bilaterally. There was no hepatosplenomegaly or palpable abdominal mass. Laboratory data were essentially negative as were intravenous pyelography (IVP), barium enema, and plain radiographs of the spine and pelvis. Chest and abdominal (Fig. 1 A) radiographs demonstrated lateral displacement of the paravertebral pleural reflections bilaterally just above the diaphragm. A radionuclide liverspleen scan was normal. Radionuclide venography demonstrated bilateral iliac vein occlusion with collateral circulation in the anterior abdominal wall and retroperitoneum on both sides. No vena cava was demonstrated in the upper abdomen. An abdominal CT scan showed numerous irregular densities in the retroperitoneum of the upper abdomen, surrounding and partially obscuring the aorta and inferior vena cava. The pancreatic head appeared slightly prominent and irregular in contour (Fig. I B). In addition, there were retrocrural rounded soft tissue densities on both sides as well as in the lower intrathroacic paravertebral regions (Fig. 1D and F). The appearances at CT were suggestive of extensive neoplasm in the retroperitoneal and posterior mediastinal lymph nodes with a possible primary t u m o r in the head of the pancreas. A CT guided percutaneous aspiration biopsy of the head of the pancreas, however, revealed normal ductal epithelium with no evidence of tumor. Exploratory laparotomy was planned but was later cancelled as it was felt that the long history and the patient's general condition were inconsistent with a diagnosis of malignant disease. He was discharged and had a follow-up CT scan two m o n t h s later. The appearances at this examination were essentially unchanged. It was appreciated at this time, however, that the previously described abnormalities could all be explained on the basis of large venous collateral vessels in association with vena caval thrombosis and occlusion. This was confirmed by intravenous bolus injection of contrast during the scanning, which identified the vascular origin of the lesions (Fig. I C, E, and G). Since no underlying cause for his venous thrombosis was found, the patient was treated symptomatically and discharged.

M.K. Wolverson et al. : CT of Venous Pseudotumors ices. Selective celiac and superior mesenteric arteriography (Fig. 2C) demonstrated portal vein occlusion with massive collateral vessels traversing the region of the occlusion in a position corresponding to the masses seen at CT. No cause for the portal vein occlusion was demonstrated, and cavernous transformation of the portal vein was diagnosed. At laparatomy, there was no evidence of retroperitoneal lymphadenopathy. The masses shown at CT were found to correspond to enlarged venous collateral vessels in association with portal vein occlusion. Splenectomy was performed and a splenorehal shunt fashioned. The venous mass in the region of the pancreatic head enhanced while scanning during bolus injection of contrast at a follow-up CT scan performed six m o n t h s later. It had diminished a little in size following the surgical decompression (Fig. 2B). Case 3

A 51-year-old diabetic m a n was referred for assessment of painless jaundice of one m o n t h ' s duration. Liver cirrhosis and portal hypertension had been diagnosed 10 years previously. There was no history of alcohol abuse, and the etiology of his cirrhosis was unclear. On physical examination, the sclerae were icteric, and spider telangiectasias were noted over the upper trunk and neck. The liver was palpable three finger breadths, but neither the spleen nor any masses were felt. Laboratory data included a total protein of 7 g/100 ml, albumin 2.8 g/100 ml, bilirubin 4.8 mg/ml, serum amylase 32 Somogyi units, alkaline phosphatase 489 units, SGOT 83 units. SGPT 100 units, lactate dehydrogenase 287, hemoglobin 12 g/100 ml, WBC 4.100/mm 3. A radionuclide liver-spleen scan showed findings consistent with cirrhosis of the liver. A C T scan of the a b d o m e n showed calcifications in the head of the pancreas consistent with pancreatitis. In the left mid a b d o m e n there was a lobulated mass of soft tissue density (Fig. 3A) that was thought to represent matted bowel loops. The mass, however, failed to opacify at repeat scanning after more oral contrast was given. Intravenous bolus injection of contrast showed dense opacification of several contiguous tubular structures that made up the whole of the mass, proving that it consisted of enlarged veins (Fig. 3 B).

Case 2

A 21-year-old m a n presented with a two-week history of melena. There was no relevant past medical history. At physical examination, he was found to be clinically anemic, and his spleen was palpable 8 cm below the costal margin. The liver was not palpable, and there were no abdominal masses or dilated abdominal wall veins. There were no cutaneous stigmata of chronic liver disease. The stool was strongly positive for occult blood. Hematological examination revealed a hemoglobin of 3.9 g/100 ml hematocrit of 23%, WBC count of 6,000/mm 3 with a normal differential count, and a platelet count of 69,000/mm 3. Bone marrow aspiration revealed erythyroid hyperplasia only. Abdominal lymphoma was considered a possible diagnosis, and a CT scan was performed (Fig. 2A). This revealed splenomegaly and mass-like densities in the retroperitoneum at the level of the head of the pancreas, as well as obscuration of the aortic and inferior vena caval contours in this region. No abnormality was seen in the liver, which appeared normal in size. L y m p h o m a was considered a likely explanation for the apparent retroperitoneal lymphadenopathy and splenomegaly. While a gastrointestinal series revealed no obvious esophageal varices and no cause for the bleeding, endoscopy and a repeat esophogram showed esophageal var-

Fig. 1 A-G. A Plain radiograph of upper abdomen. Note lateral displacement of the lower paravertebral pleural reflections (arrows).

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Fig. IB, C. CT scan at level of the head of the pancreas. B Before contrast injection. Note the numerous nodular densities in the retroperitoneum (arrows). C During intravenous contrast injection. The nodules enhance indicating their vascular nature (arrows). D, E. CT scan at the level of the xiphoid. D Before contrast injection. There are rounded densities in the retrocrural and right paravertebral regions (arrows). E During intravenous contrast injection, The masses enhance indicating that they are veins (arrows), F, G. CT scan through the lower chest. F Before contrast injection, There are paravertebrat rounded soft tissue densities (arrows). G During intravenous contrast injection. The soft tissue masses enhance during contrast injection, indicating that they are vessels

(arrows).

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Fig. 2 A - C . A C T scan through the upper abdomen. There are mass-like densities in the retroperitoneum and prominence of the pancreatic head (arrows). There is obscuration of the great vessel contours. The spleen is enlarged. B CT scan six m o n t h s after operation. During intravenous contrast injection there is marked enhancement of the mass in the region of the pancreatic head indicating its vascular origin (arrows), C Venous phase of superior mesenteric arteriogram. Massive collateral veins are seen replacing the portal vein (arrows).

Fig. 3A, B. CT scan through midabdomen. A Before contrast injection. There is a lobulated soft tissue mass in the left side of the a b d o m e n (arrows). B During contrast injection. Marked enhancement of the mass occurred (arrows).

A diagnosis of venous pseudotumor in association with portal hypertension was made. Liver biopsy showed macronodular cirrhosis, and the patient's jaundice was assumed to be due to hepatocellular failure. His jaundice subsided spontaneously, and he was discharged to the care of his family physician.

Case 4 A 10-year-old girl was admitted for assessment of liver enlargement that had been first noted at the age of 13 months. Laparotomy at that time demonstrated a massive, red. firm liver and examina-

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Fig. 4 A - E . A Plain radiograph of upper abdomen. There is lateral displacement of the lower left paravertebral pleural reflection (arrows). B CT scan through lower chest. There are paravertebral soft tissue densities bilaterally (arrows). C CT scan at the level of the xiphoid. During intravenous contrast injection there is enhancement of the left paravertebral soft tissue density indicating its vascular nature. D, E Inferior vena cavogram. D early, and E late films in the series. There is marked narrowing of the intrahepatic portion of the inferior vena cava (small arrows). Flow in the upper cava is interrupted and redirected through the left renal, ascending lumbar, hemiazygous, and spinal plexus o f veins (large arrows).

tion of a biopsy specimen showed "passive congestion" only; no cause for her liver disease was found. She remained well until her current admission when at physical examination the liver was palpable 6 cm below the costal margin as a firm mass with a nodular surface. The spleen was not palpable. There were cutaneous spider angiomata and finger clubbing.

Laboratory data revealed normal liver-function and hematological tests. Plain chest and abdominal radiographs (Fig. 4A) showed lateral displacement of the lower left paravertebral stripe indicating posterior mediastinal widening and prominence of the azygous vein above the right lung hilum. A C T scan of the chest and the a b d o m e n showed diffuse liver enlargement and nodular thickening of the posterior intrathoracic paravertebral soft tissues corresponding to the appearance seen on the plain films (Fig. 4B). Further images obtained during intravenous bolus injection of contrast showed opacification of the paravertebral densities, indicating their vascular nature (Fig. 4C). In addition, the intrahepatic portion of the inferior vena cava appeared as a narrow cleft compressed from both sides by the enlarged liver. An inferior vena cavogram (Fig. 4 D and E) confirmed marked intrahepatic narrowing of the cava due to extrinsic compression. Enlarged paravertebral and hemiazygous collateral veins redirected much of the caval flow through the diaphragm to the posterior mediastinum. These veins corresponded to the masses shown at CT. At open liver biopsy, the liver appeared diffusely hard and nodular. There was no evidence of intra-abdominal tumor. The biopsy showed changes of micronodular cirrhosis and evidence of diffuse long-standing hepatic venous occlusive disease. The final

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M.K. Wolverson et al. : CT of Venous Pseudotumors

Fig. 5A-C. CT scan through upper abdomen. A Before contrast injection. There are numerous nodular densities surrounding the great vessels and m the adjacent retroperitoneum, especially on the left side (arrows). B During intravenous contrast injection. The nodules enhance considerably indicating that they are vessels (arrows) C Venous phase of celiac arteriogram Numerous dilated and tortuous veins are seen emanating from the hilum of the enlarged spleen (arrozc~). No normal splenic vein was seen.

diagnosis was idiopathic Budd-Chiari syndrome complicated by hepatic cirrhosis. The child was discharged on 11o treatment in good condition.

Case 5 A 51-year-old woman was operated on for a bleeding duodenal ulcer in October 1975. At surgery, in addition to the bleeding ulcer, she was found to have an unresectable tumor of the head and adjacent body of the pancreas, which was shown to be an islet cell tumor on examination of a biopsy specimen. Amrectomy and vagotomy were performed. The results of postoperative laboratory studies, including normal blood gastrin levels, failed to support a diagnosis of Zollinger-Ellison syndrome. During a nine-month course of tumor chemotherapy with streptozotocin, there was angiographic demonstration of decrease in the size of the tumor. The drug was then discontinued because of liver toxicity, and further treatment was by implantation of radioactive iodine-125 seeds into the tumor at laparotomy. The patient remained well until December 1977 when she developed jaundice due to obstruction of the common bile duct by the tumor. Cholecystectomy and choledochoduodenotomy were performed. [n January 1979 a CT scan of the abdomen showed a mass in the head and body of the pancreas. The spleen was enlarged. Numerous nodular densities were seen surrounding the great vessels and adjacent retroperitoneum, especially on the left (Fig. 5A). These were interpreted as representing spread of the tumor to surrounding lymph nodes. Intravenous contrast was given, but

not as a bolus injection, and no obvious abnormal vascular structures were appreciated. The patient was well until December 1979 when she was admitted with gastrointestinal bleeding found to be due to gastric mucosal erosions. A repeat CT scan at this time showed no change, but the possibility of venous pseudotumour in association with neoplatic occlusion of the splenic vein was considered to account for the retroperitoneal nodular densities. This was confirmed by intravenous bolus injection of contrast during scanning (Fig. 5B) and by arterial portography (Fig. 5C). At arteriography, the tumor was shown to be unchanged in size since the previous stud}' three years before.

Discussion A n o m a l o u s veins, due to congenital variations of the inferior vena cava, have been demonstrated at CT in the retroperitoneum and retrocrural space [10-12]. Similar appearances near the diaphragm were seen in two of our patients. They were caused by dilation of azygous and hemiazygous collateral veins due to post-thrombotic inferior vena caval occlusion in one (Case 1) and caval compression by an enlarged liver in the other (Case 4). Detection of thrombosis of the

M.K. Wolverson et al. : CT of Venous Pseudotumors inferior vena cava a n d its i n v a s i o n by t u m o r at C T has been described [15, 16], but there have been n o previous reports of d e m o n s t r a t i o n of collateral veins in acquired caval occlusion or compression. Ishikiwa et al. have f o u n d venous a b n o r m a l i t i e s at C T in the chest a n d / o r a b d o m e n of a high p r o p o r tion of subjects with portal h y p e r t e n s i o n [13]. In three of our patients, r e t r o p e r i t o n e a l n e o p l a s m was simulated by collateral veins that developed as a result of extrahepatic portal o b s t r u c t i o n in two (Cases 2 a n d 5) a n d by p o s t - t h r o m b o t i c caval o b s t r u c t i o n in the third (Case i). Portal systemic collateral veins occur in the r e t r o p e r i t o n e u m in portal h y p e r t e n s i o n a n d in inferior vena caval occlusion [17-19], especially where there are bare visceral surfaces in contact with somatic tissues, e.g., d u o d e n u m , pancreas, spleen, a n d liver. In caval occlusion m u c h of the collateral flow is t h r o u g h the ascending l u m b a r , l u m b o a z y g o u s , a n d g o n a d a l veins [20]. A t C T these various collateral veins may a p p e a r either as discrete masses between the aorta or inferior vena cava and the psoas muscles or as poorly d e m a r c a t e d tissue s u r r o u n d i n g and obscuring these great vessels or the c o n t o u r s of the pancreas. I n a cirrhotic patient (Case 3) a mass in the left a b d o m e n was s h o w n to be due to dilated veins in a position c o r r e s p o n d i n g to the d i s t r i b u t i o n of the inferior mesenteric vein. Mesenteric varices are unc o m m o n , a n d their occurrence has been related to the d e v e l o p m e n t ofcoUaterals at the site of postoperative or i n f l a m m a t o r y adhesions [21]. A n e m b r y o l o g i c rationale for their d e v e l o p m e n t has also been provided by E d w a r d s [17] a n d this m a y apply to our case since there was n o history of surgery or infection. Initial m i s i n t e p r e t a t i o n of the C T images in two of our patients led to the c o n s i d e r a t i o n o f l a p a r o t o m y for diagnosis (Cases 1 a n d 5), a n d one of them had a n unnecessary needle biopsy of the head of the pancreas (Case 1). L y m p h o m a was considered the p r o b a b l e cause of the C T findings in one subject (Case 2), the correct diagnosis being m a d e at angiogr a p h y a n d l a p a r o t o m y . In a n o t h e r patient, with a k n o w n pancreatic t u m o r , a false i n t e r p r e t a t i o n of spread of the disease was m a d e at the first C T study

(Case 5). A t C T there is n o appreciable difference in the x-ray a t t e n u a t i o n of these vessels c o m p a r e d with neoplastic nodes on the precontrast scans. After c o n t r a s t injection, if s c a n n i n g is delayed for several m i n u t e s in the area of interest, n o appreciable a t t e n u a t i o n increase m a y be observed. R a p i d sequential s c a n n i n g d u r i n g bolus injection of c o n t r a s t ensures that images are o b t a i n e d with the vessels densely opacified. Identification in this way eliminates the need for formal a n g i o g r a p h y to characterize these lesions.

157 L i m i t a t i o n s in the C T diagnosis of retroperitoneal lymph n o d e disease have recently been emphasized by Williams [14], a n d our experience indicates that dilated collateral venous channels in association with portal h y p e r t e n s i o n a n d inferior vena caval interruption should be included in this differential diagnosis.

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