Multiple Splenic Artery Aneurysms: A Rare Cause of Extrahepatic Portal Hypertension and Massive Splenomegaly

A 39-year-old nulliparous female was admitted with massive splenomegaly. Computed tomography of abdomen revealed multiple aneurysms in the distal half of the splenic artery. Splenic artery aneurysms are rare in nulliparous women and most cases are reported in females with a past history of pregnancy. Splenic artery aneurysms, though very rare are clinically significant as they have a high propensity for fatal rupture. Here, we report a patient with multiple splenic artery aneurysms presenting as extrahepatic portal hypertension and massive splenomegaly.

A 39-year-old female presented with one year history of dragging abdominal discomfort and fatigability of six months duration. She was non-alcoholic and had no other medical illness. General physical examination was unremarkable and abdominal palpation suggested splenomegaly of 10 cms below left coastal margin, which was firm and nontender. There was no ascites or hepatomegaly. Examination of other systems was unremarkable.

Investigations revealed normal complete blood counts, urine analysis, liver and renal function tests and peripheral smear study. Investigation reports are shown in [Table/Fig-1]. Ultrasonography (US) with color doppler of abdomen revealed splenomegaly, normal liver echotexture and cavernous transformation of portal vein with multiple spleno-renal collaterals. ECG and echocardiography was normal. Upper gastro-intestinal endoscopy showed grade 1-2 esophageal varices with portal hypertensive gastropathy. Multidetector Computed tomography (MDCT) abdomen revealed multiple aneurysms in the distal half of splenic artery, the largest one measuring (5.1cmx5.8cmx4.4cms) with dilated and tortuous course of the proximal splenic artery with multiple collaterals along the course of splenic and portal vein [Table/Fig-2a,b,3a-c]. Wall calcification and organized thrombus was seen in few of the aneurysms at the splenic hilum.

[Table/Fig-2]:

A: Multiple aneurysms in the distal half of splenic artery, three of them abutting medial surface of spleen. B- Aneurysms at the splenic hilum show wall calcification and intraluminal thrombus. Splenomegaly with multiple, coarse calcifications

[Table/Fig-3]:

A- Tortuous, large calibre collateral venous channels noted along the course of splenic vein and portal vein. B- 3 D image showing dilated splenic artery and multiple aneurysms. C- Angiogram showing large fusiform aneurysm

Splenic artery aneurysms (SAA) are the most common visceral aneurysms, accounting for up-to 60% of cases [1,2]. Splenic artery is the third most common site for intra-abdominal aneurysm after aorta and iliac artery [2]. It has an incidence of 0.01-0.2%, females being more commonly affected (4:1). SAA presenting as extra-hepatic portal hypertension is rare [1,3]. Here we report a patient with multiple splenic artery aneurysms presenting as extrahepatic portal hypertension and massive splenomegaly.

SAA are very rare with a varied prevalence of 0.01%-10.4% [4]. SAAs are associated with several conditions, including pregnancy, degenerative atherosclerosis, portal hypertension, medial fibrodysplasia, arteritis, collagen vascular disease, α1-antitrypsin deficiency, and pancreatitis [2]. Hormonal changes during pregnancy, increased blood volume and cardiac output causing portal congestion are the proposed mechanisms of SAA in pregnancy [5]. SAA are usually single, isolated and <3cms in size. It is usually located in the distal part of splenic artery. Larger aneurysms like in our patient are seldom reported [1,3,6]. The aneurysm generally develops on the main splenic artery commonly on its distal third or on intrasplenic branches.

SAA are usually asymptomatic but are increasingly diagnosed as incidental findings. However, epigastric or left hypochondrial pain can be the presenting symptom in some patients. Rarely it can manifest with features of extra-hepatic portal hypertension [1,3]. Catastrophic complication includes rupture, which is more common with pregnancy [5] and larger aneurysms. Splenic infarction may rarely complicate aneurysms due to embolisation of the clot. Rarely, the aneurysm may erode into the stomach causing upper gastrointestinal haemorrhage.

Modern imaging techniques allow early detection of asymptomatic aneurysms [7]. Direct catheter angiography, although is gold standard for diagnosing SAA needs arterial puncture. With the advent of MDCT, aneurysms can be easily detected. On contrast enhanced CT, aneurysms may appear well defined and homogenous. An unruptured SAA may be misinterpreted as a pancreatic mass on CT, as islet cell tumors can be hyper-attenuating in the arterial or pancreatic phase. However, 3D imaging augments the accuracy in diagnosing SAA. Treatment options include aneurysmectomy, trans-catheter embolisation with coils or stent graft placement with or without splenectomy.

This case presented with abdominal pain and was found to have massive splenomegaly on evaluation. Liver function tests were normal with normal serum albumin, liver enzymes and prothrombin time. Ultrasonography of abdomen did not reveal any changes in liver echotexture. Normal hematological parameters and absence of lymphadenopathy excluded haematological cause for massive splenomegaly. Presence of esophageal varices and congestive gastropathy on endoscopy in the setting of normal liver functions pointed towards extrahepatic portal hypertension as the most probable diagnosis. Further evaluation revealed multiple SAA in the distal half of the artery.

As per the literature,multiple SAA are uncommon accounting for upto 20% of cases [8]. Cavernous transformation of the portal vein is likely to be due to multiple SAA causing extrinsic compression of splenic vein, leading to venous stasis and thrombosis of splenic and portal vein. This is the most likely explanation for splenomegaly and portal hypertension in our patient. A case of multiple SAAs caused by fibromuscular dysplasia (FMD) has been reported by Watada S et al., [9]. FMD could be the explanation for multiple aneurysms in our patient.

Extrahepatic portal hypertension is a rare presentation of SAA. SAA detection in the clinical scenario of extrahepatic portal hypertension is of utmost importance, as it is curative and treatment can prevent mortality.

[1]. Ali Sadaf, Verma Vibha, Sastry R, Wani Imtiaz, Giant Splenic Artery Aneurysm Case Report International Scholarly Research Network ISRN Surgery Volume 2011 :383450doi:10.5402/2011/383450  [Google Scholar]

[2]. Kim Youngjin, Johna Samir, Laparoscopic Excision of Splenic Artery Aneurysm Journal of the Society of Laparoendoscopic Surgeons 2013 17:132-34.  [Google Scholar]

[3]. Elamurugan T. P., Kumar S. Suresh, Muthukumarassamy R, Kate Vikram, “Splenic Artery Aneurysm Presenting as Extrahepatic Portal Vein Obstruction: A Case Report,” Case Reports in Gastrointestinal Medicine 2011 2011Article ID 908529, 3 pages, 2011. doi:10.1155/2011/908529  [Google Scholar]

[4]. Zubaidi Ahmad, Rupture of Multiple Splenic Artery Aneurysms: A Common Presentation of a Rare Disease with a Review of Literature Saudi J Gastroenterol 2009 15:55-8.  [Google Scholar]

[5]. Selo-Ojeme DO, Welch CC, Review: spontaneous rupture of splenic artery aneurysm in pregnancy Eur J Obstet Gynecol Reprod Biol 2003 109:124-27.  [Google Scholar]

[6]. Yadav Siddharth, Sharma Piyush, Singh PK, Punia S, Desai P, Anjan AK, Giant splenic artery aneurysm: A rare but potentially catastrophic surgical challenge Int J Surg Case Rep 2012 3:533-36.  [Google Scholar]

[7]. Chu-Feng Liu, Chia-Te Kung, Ber-Ming Liu, Shu-Hang Ng, Chung-Cheng Huang, Sheung-Fat Ko, Splenic artery aneurysms encountered in the ED:10 years’ experience American Journal of Emergency Medicine 2007 25:430-36.  [Google Scholar]

[8]. Agarwal Aditya, Whitehouse Richard, Johnson Robert W, Augustine Titus, Giant splenic artery aneurysm associated with arteriovenous malformation Journal of Vascular Surgery 2006 44:1345-49.  [Google Scholar]

[9]. Watada S, Obara H, Shimoda M, Matsubara K, Multiple aneurysms of the splenic artery caused by fibromuscular dysplasia Ann Vasc Surg 2009 23:411.e5-7doi:10.1016/j.avsg.2008.04.015  [Google Scholar]