症例報告

Numerous Arterial Aneurysms associated with Segmental Arterial Mediolysis
村上 健司１＊、佃 彰文１、植田 はるか１、鎌田 紀美男１、一色 裕之 2Kenji Murakami ＊ , Akifumi Tsukuda, Haruka Ueda, Kimio Kamada, Hiroyuki Isshiki
1 函館五稜郭病院 放射線診断科、2 消化器内科
1 Department of Diagnostic Radiology, Hakodate Goryokaku Hospital, Hakodate,Japan
2 Department of Gastroenterology, Hakodate Goryokaku Hospital, Hakodate,Japan

2022 年 4 月 13 日論文受領、修正依頼 5 月 20 日、最終受領日 6 月 1 日【要旨】症例は 70 歳代男性。下血・貧血を認め、来院した。
CT を撮影すると肝動脈、脾動脈、腎などを含め多数の動脈瘤を認めた。特に膵十二指腸（下膵十二指腸動脈）の仮性動脈瘤は急速増大し、破裂していると考えられたため、塞栓術を行った。フォローの CT で血流は消失。下血は消失した。フォロー CT で塞栓した動脈瘤を含め、多発動脈瘤は経過観察にて緩徐に縮小した。3 年度経過した現在も再燃なし。SAM と考えられた多発仮性動脈瘤の一例を経験したので、文献的考察を含め報告する。
【責任著者】村上 健司〒 040-8611 函館市五稜郭町 38 番 3 号 Tel：0138-51-2295 FAX0138-56-2695 E-mail：muraken1029@gmail.com【キーワード】Endovascular treatment、Aneurysm、Segmental Arterial Mediolysis【利益相反】開示すべき利益相反状態はない【グラント】なし【Abstract】A man in his 70s presented with rectal hemorrhage. Computed tomography demonstrated numerous visceraland renal aneurysms, compatible with segmental arterial mediolysis（SAM）, and a ruptured pancreaticoduodenal arteryaneurysm. Transcatheter arteriography demonstrated multiple aneurysms located on the branches of the celiac artery,superior mesenteric artery, and renal arteries. The pancreaticoduodenal artery aneurysm was embolized with detachable
coils, which improved the melena. Follow-up computed tomography at 3 years demonstrated that the remaining
untreated aneurysms had disappeared spontaneously. Aneurysms of the abdominal visceral arteries due to SAM arecommon, but numerous aneurysms in a single patient are extremely rare. This patient had numerous aneurysms
associated with SAM and received treatment only for the ruptured aneurysm, which was associated with a good clinicaloutcome.

【Introduction】【Case report】

Segmental arterial mediolysis（SAM）was first recognized

A man in his 70s presented with fever for 3 weeks andby Slavin and Gonzalez-Vitale in 1976 as a non-inflammatory

elevated liver enzyme levels. His past medical history

and non-arterosclerotic degenerative disease that affects

was significant for hepatitis B virus infection. CT showed

the arteries. We present a case of SAM in a patient whonumerous aneurysms including, but not limited to, the celiac

developed numerous aneurysms. Only the ruptured

and superior mesenteric arteries and renal artery（Fig. 1）.

aneurysm was treated, whereas the other aneurysms wereHis symptoms improved without treatment. However, after

followed up with computed tomography（CT）. Follow-up CT

6 days, he experienced abdominal pain and melena. His blooddemonstrated disappearance of all aneurysms.

tests showed a hemoglobin level of 6.0 mg/dL, negative

This case report was approved by our Institutional Review
Board（no.：2020-063）.

cultures, and negative antibodies for polyarteritis nodosa andother vasculitis.
The second CT scan performed after 7 days showedenlargement of the previously detected aneurysms, with7

北海道放射線医学雑誌

第3巻

the largest increase observed in the pancreaticoduodenal

enlargement or pseudoaneurysm formation. The treatment

artery aneurysm, and suspicion of rupture of theplan was agreed upon by multiple departments.

pancreaticoduodenal artery aneurysm. The angiography

CT performed at 1 week, 1, 2, 3, and 6 months, and 1

showed numerous aneurysms located at the celiac andyear showed progressive decline in the sizes of multiple

superior mesenteric arteries（Fig. 2a, b）. The diameter ofaneurysms. The 3-year follow-up CT scan showed athe significantly enlarged pancreaticoduodenal aneurysm wassignificant decrease in the size of multiple aneurysms without

26 mm on CT.

any treatment（Fig. 7）. We diagnosed SAM because of theThe pancreaticoduodenal artery was significantly enlarged

test results（negative cultures, and negative antibodies forand had protruded into the duodenum, and it appeared topolyarteritis nodosa and other vasculitis）and the shrinkage

be the source of the bloody discharge.Target aneurysmof the aneurysm.

presented in posterior superior pancreaticoduodenal artery【Discussion】（PSPDA）.
We performed that embolize proximal of PSPDA,

Our patient had almost 100 SAM-induced aneurysms

distal of PSPDA, anastomotic branch of anterior superior

and underwent treatment for a single aneurysm thatpancreaticoduodenal artery（ASPDA）with coils and isolatewas considered to be ruptured. Many other aneurysms

target aneurysm.（Fig3-6）The procedure was successful

were detected but not treated due to technical difficulty；

in terminating the bloody discharge from the bowel andtherefore, the sizes of the aneurysms were followed-up by

improving the anemia. Since it was difficult to treat all ofrepeat CT.

the aneurysms, we decided to perform follow-up CT at

We decided to treat the aneurysms that demonstrated

short intervals and perform embolization in case of vessel

significant growth, suspicion of rupture, or protrusion into

Fig1 CT shows numerous
arterial aneurysms（celiac,superior mesenteric ,renalartery branch, respectively）

ab

Fig2ab Celiac（a）and superior
mesenteric angiography（b）
shows hundreds of aneurysms.
8北海道放射線医学雑誌

Fig3 Schematic drawing of the embolic procedure：
Target aneurysm present in PSPDA.
Embolize at 3 points with coils and perform isolation proximal
to PSPDA, and distal to anastomotic branch of ASPDA（yellowarrow）.

Fig5 After posterior superior pancreaticoduodenal artery
embolized, inferior pancreaticoduodenal angiography showsdistal side of target aneurysm（yellow arrow）and anastomotic
branch of ASPDA（blue arrow）

第3巻

Fig4 posterior superior pancreaticoduodenal angiographyshows the target aneurysm

Fig6 After embolization, inferior pancreaticoduodenalangiography shows no blood flow for aneurysm

9北海道放射線医学雑誌

第3巻【Conclusions】
Our patient developed numerous aneurysms due to SAM
but underwent embolization for only the ruptured aneurysm,
with a good clinical course.
【Disclosure statement】
The authors declare no potential conflicts of interest withrespect to the research, authorship, and/or publication of thisarticle.
【Additional note】
Informed consent was obtained from the patient for
publication of this paper.
【References】
1. ‌Slavin RE, Gonzalez-Vitale JC. Segmental mediolytic
arteritis：A clinical pathologic study. Lab Invest. 1976
Fig7 CT performed at 3-year follow-up shows that themultiple aneurysms had shrunk

Jul；35（1）：23-9.
2. ‌Skeik N, Olson SL, Hari G, Pavia ML. Segmental arterial
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a free space（e.g., abdominal cavity）based on the opinionsof the gastroenterologist and surgeon. All aneurysms werereduced in size during follow-up without medication use.

cases. Vasc Med. 2019 Dec；24（6）：549-63.
3. ‌Kiyoshi I, Tsuneko I, Toshiyuki H. A study on 20 casesof segmental arterial mediolysis（SAM）with multiple

SAM is a disease of unknown etiology that is associatedaneurysms-with a special reference to incidence,with medial degeneration and results in the formation oftreatment and prognosis-.Nihon Rinsyogekagakkai Zasshi.

arterial aneurysms. Recent reports state that almost 66% of69（12）, 3101-3106, 2008patients have multiple aneurysms. However, the maximum

4. ‌Pillai AK, Iqbal SI, Liu RW, Rachamreddy N, Kalva SP.

number of previously reported aneurysms was less thanSegmental arterial mediolysis. Cardiovasc Intervent

20, with no reports of as many aneurysms as present in ourRadiol. 2014 Jun；37（3）：604-12.

patient.
In our patient, only the ruptured aneurysm was treatedwith embolization, whereas the residual aneurysms decreased

5. ‌Ryan JM, Suhocki PV, Smith TP. Coil embolization ofsegmental arterial mediolysis of the hepatic artery. J VascInterv Radiol. 2000；11：865-8.

in size during follow-up, and the patient had a good clinical

6. ‌Michael M, Widmer U, Wildermuth S, Barghorn A,course. SAM aneurysms are at high risk of rupture, andDuewell S, Pfammatter T. Segmental arterial mediolysis：

ruptured aneurysms are treated with vascular embolization.

CTA findings at presentation and follow-up. American

However, the condition is often fatal if treatment is delayed.

Journal of Roentgenology. 2006 Dec；187（6）：1463-9.

4,5）
The natural history of aneurysms is unclear, and manyaneurysms decrease in size without treatment. 6）Ruptured
aneurysms must be treated, whereas non-ruptured
aneurysms may shrink without treatment during follow-up.

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