CASE 14571 Published on 25.03.2017

Anomalous splenic vein, extending to the pelvis

Section

Abdominal imaging

Case Type

Anatomy and Functional Imaging

Authors

Schiaffino S., Zaottini F., Massone E., Piccazzo R., Melani E., Rollandi G.A.

University of Genoa,
Largo Rosanna Benzi 10,
16132, Genova, Italy;
Department of Radiology.
Ospedale Galliera.
Genova. Italy
Patient

48 years, male

Categories
Area of Interest Veins / Vena cava ; Imaging Technique CT, CAD
Clinical History
A 48-year-old man presented to the radiology department for CT check because of clinical history of tuberculosis. He was dyspnoeic and had elevated inflammatory markers.
Imaging Findings
The patient had active pulmonary tuberculosis. The CT examination, extended to the abdomen, revealed an anomalous splenic-portal confluence and anomalous splenic vein anatomy. Arising from the splenic hilum, the vein passed anterior to the anterior edge of the spleen, to its lower pole, and continued its intra-peritoneal course along the abdominal wall in the left paracolic recess, entered in the pelvis and ended up at the level of the bladder base. Then it turned up behind the posterior surface of the left rectus abdominis muscle to reach the greater gastric curve, ran medially toward the gallbladder fundus, turned medially and reached the superior mesenteric vein, superiorly to the pancreatic head.
No venous vessel was present in the normal splenic vein course. The pancreatic venous vessels were more apparent in the parenchyma, due to drainage compensation.
The gastroepiploic vein was normally present, and communicated with the anomalous splenic vein at the level of the splenic hilum.
Discussion
The splenic vein embryology starts from the two vitelline veins, the first of all the veins to be developed. The right vitelline vein forms the superior mesenteric vein. The proximal portion of the left vitelline vein disappears during development. The terminal parts of the two vitelline veins are joined by three transverse communications, the middle one lies in the dorsal aspect of the duodenum, where it is reached by the splenic and inferior mesenteric vein [1].
During this development, splenic vein abnormalities may occur, but they are rare. A search of Pubmed and Medline revealed only one case report describing an anatomic variant of splenic vein [2].
During development, the splenic vein runs in the dorsal mesogastrium (Fig. 1), an embryological structure that begins to form during the fourth week of gestation and will give origin to the splenic ligaments including the gastrolienal ligaments and continue as the lesser omentum and hepato-duodenal ligaments.
In our case the splenic vein was not included in these peritoneal structures. We know that the greater omentum derives from the dorsal mesogastrium folding upon itself, anterior to the transverse colon and small bowel [3]. We think that the anomalous vein results from the persistence of a connecting vein running inside the greater omentum, probably one of omental vein tributary [4], instead of the lesser omental bursa, but it is arduous to find a definitive explanation.
Identifying anatomic variants of the portal system is important in the surgical planning of different interventional procedures [5]. The portal system abnormalities are crucial for hepatic surgery, but in the presented case almost every abdominal surgical intervention could be at risk of splenic vein damage, with potential risk of severe bleeding. Laparotomic access could pose the risk of bleeding, as the laparoscopic one, because of potential damage derived from trocar accesses. Percutaneous interventional procedures, such as paracentesis, could be dangerous too. Furthermore, the anomalous course could pose the risk of thrombosis for slowed blood flow.
This singular anatomic variant underlines the importance of deep knowledge of embryology for the comprehension of anatomic variants in the human body. This case suggests the relevance of pre-operative imaging assessment for a better surgical planning.
Differential Diagnosis List
Anomalous splenic vein
Anomalous splenic vein
Portosystemic shunt
Final Diagnosis
Anomalous splenic vein
Case information
URL: https://eurorad.org/case/14571
DOI: 10.1594/EURORAD/CASE.14571
ISSN: 1563-4086
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