Case reports

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reported the first case of a splenic vein aneurysm. (SVA) (1). Since then, increasing numbers of aneurysms of the portal venous system have been reported (2-6).
Case reports Acta chir belg, 2004, 104, 322-324

Aneurysm of the Splenic Vein M. Heeren*, B. Op de Beeck**, P. Van den Brande* Departments of Vascular Surgery* and Radiology**, Academic Hospital Vrije Universiteit Brussel, Brussels, Belgium.

Key-words. Aneurysm ; vein ; splenic ; portal. Abstract. Aneurysms of the portal venous system are increasingly reported in the past five years. Congenital weakness of the venous wall, trauma, pancreatitis and portal hypertension are possible etiologies. Surgical intervention is indicated in case of symptomatic aneurysms with or without progressive expansion of the aneurysm diameter. The treatment of asymptomatic splenic vein aneurysms remains debated. We report the case of an asymptomatic and uncomplicated splenic vein aneurysm for which a conservative approach was advocated with regular follow-up by means of Doppler ultrasonography. After six years of follow-up the aneurysm diameter has not changed and no complications were observed. Introduction Aneurysms are defined as abnormal dilatations of vessel walls. Although this definition is mostly restricted to arterial and cardiac structures, it is applicable to the venous system as well. In 1953, Loewenthal and Jacob reported the first case of a splenic vein aneurysm (SVA) (1). Since then, increasing numbers of aneurysms of the portal venous system have been reported (2-6). Possible etiologies of SVAs include portal hypertension, trauma, pancreatitis, and congenital weakness of the venous wall. Symptomatic splenic vein aneurysms can present with abdominal or back pain, portal hypertension or free intraperitoneal haemorrhage (2-4). In these cases, urgent surgical intervention is mandatory. The best treatment strategy for accidentally found asymptomatic SVA remains controversial. Some authors apply regular follow-up by means of CT-scanning (2), while others advocate a surgical intervention before any complication occurs (4). We present the case of an accidentally found and conservatively managed SVA remaining asymptomatic after a six-year follow-up.

the pancreatic region. Contrast-enhanced CT-scanning revealed a lesion that seemed to be localised in the pancreas. Magnetic resonance imaging (MRI) of the abdomen showed the presence of a three centimeter well-circumscribed mass with low signal intensity in T1weighted sections and high signal intensity in T2-weighted sections, suggesting a vascular tumor. After contrast enhancement the mass became filled with contrast product only two seconds after filling of the abdominal aorta and at the same time as the splenic parenchyma (Fig. 1). Selective coeliac angiography showed the presence of a three centimeter wide localized dilatation of

Case report A 43-year-old caucasian female was admitted for preoperative investigation for a lump in the left breast. She had no history of alcohol abuse, jaundice, pancreatitis or trauma, nor any complaints of abdominal pain. Abdominal masses were not palpable and there was no hepato- or splenomegaly, nor any other sign of portal hypertension. Abdominal ultrasound was performed to exclude possible liver metastases. This showed the presence of a hypo-echogenic mass of unknown origin in

Fig. 1 Contrast enhanced MRI-imaging of the abdomen showing splenic vein aneurysm (A, indicated by black arrow) and spleen (S).

Aneurysm of the Splenic Vein

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the splenic vein (Fig. 2). The patient underwent segmentectomy and axillary dissection for the mass in her left breast, which turned out to be an infiltrating ductal carcinoma. Because of the asymptomatic character of the SVA in this patient, no surgical intervention was performed. After six years of follow-up by means of Doppler ultrasonography the diameter of the aneurysm has remained stable and the patient does not have any complaints or signs of abdominal discomfort or portal hypertension.

might be involved, but some degree of congenital weakness of the venous wall is supposed to be the underlying condition (2-4). Our patient had not undergone any significant trauma, did not have a history of pancreatitis nor any signs of portal hypertension. Therefore, congenital weakness of the vein wall can only be supposed at best as the underlying mechanism of the SVA in our patient. Increasing performance and sensitivity of radiographic examinations of the abdomen might diagnose asymptomatic portal venous aneurysms more frequently. Because the natural history of these accidentally found lesions is unclear, there is much controversy about their treatment. Only six cases of SVAs have been published since its first autopsy report in 1953 (1). History, treatment and outcome of these cases (2-7) are listed in Table I. These data show the variety of presentations, leading to different opinions about the optimal treatment

Discussion A number of possible etiological mechanisms for the development of splenic vein aneurysms have been postulated. Trauma, pancreatitis or portal hypertension

Table I History, treatment and outcome of six reported cases of SVAs Authors

Symptoms/signs

Treatment

Follow-up

SOO et al. (2)

Accidental finding in asymptomatic patient

Conservative

?

OHHIRA et al. (3)

Liver cirrhosis, portal hypertension, hepatoma

Conservative

Gradual enlargement, death by metastatic disease

TORRES et al. (4)

Abdominal and back pain in young woman without portal hypertension

Aneurysm excision and splenectomy

SHIROHARA et al. (5) Liver cirrhosis SCHMIDT (6)

Conservative

Admission for suspected pancreatic pseudocyst Conservative

TOLGONAY et al. (7) Splenomegaly in patient with leucemia

Fig. 2 Venous phase of celiac angiography showing well circumscribed dilatation of splenic vein (black arrow).

Gradual enlargement ?

Chemotherapy, no surgical treatment Regression of aneurysm diameter and splenomegaly after chemotherapy

of a SVA. Some authors suggest that prophylactic surgical intervention should be considered in asymptomatic cases because of the high rate of complications eventually survening (4). However, follow-up data are scarce and some SVAs remain uncomplicated or even regress with non-surgical conservative treatment. In our patient the SVA diameter did not change during six years of follow-up and complications did not occur. Therefore we only recommend surgical excision in case of gradually enlarging and/or symptomatic SVAs. Venous aneurysms of the portal system can be misdiagnosed as a pancreatic mass or an aneurysm of the splenic artery on CT- and MRI-imaging studies (2). Therefore, we would recommend to perform a selective coeliac angiography for any lesion with vascular characteristics on MRI-imaging, presumed to be located in the pancreas (insulinoma, glucagonoma). Besides, preventing a missed diagnosis of a splenic vein aneurysm, it will avoid performing CT-guided biopsy of these lesions with potentially catastrophic consequences.

324 References 1. LOEWENTHAL M., JACOB H. Aneurysm of the splenic vein — report of a case. Acta Med Orient, 1953, 12 : 170-3. 2. SOO M. S., KHOURY M. B., LUPETIN A. R. Splenic vein aneurysm : MR-appearance – a case report. Angiology, 1991, 42 : 590-3. 3. OHHIRA M., ONO M., OHHIRA M., MATSUMOTO A., OHTA A., NAMIKI M. Splenic vein aneurysm — report of a lesion that progressively expanded. Br J Radiol, 1994, 67 : 656-8. 4. TORRES G., HINES G. L., MONTELEONE F., HON M., DIEL J. Splenic vein aneurysm : is it a surgical indication ? J Vasc Surg, 1999, 29 : 719-21. 5. SHIROHARA H., ENDO M., SAKAI K., TABARU A., OTSUKI M. Enlarging splenic vein aneurysm associated with stagnation of splenic venous blood flow. Am J Gastroenterol, 1996, 91 : 385-7.

M. Heeren et al. 6. SCHMIDT H. G. Splenic vein aneurysm : diagnosis with color-coded duplex ultrasound. Leber Magen Darm, 1995, 25 : 227-8, 231. 7. TOLGONAY G., OZBEK S. S., ONIZ H., SUZER E., YURDAKUL L. O. Regression of splenic vein aneurysm following resolution of splenomegaly. J Clin Ultrasound, 1998, 26 : 98-102.

P. Van den Brande Department of Vascular Surgery Academic Hospital Vrije Universiteit Brussel Laarbeeklaan, 101 1090 Brussels Tel. : 32 2 477 78 69 Fax : 32 2 477 65 05