Segmental Mediolytic Arteriopathy Involving Celiac to Splenic and Left Renal Arteries
Chisa TAKAGI, Naoto ASHIZAWA, Kiyoyuki EISHI*, Kazuto ASHIZAWA ** , Tomayoshi HAYASHI *** , Kyoei TANAKA, Shinji SETO and Katsusuke YANO
Abstract
A 46-year-old man presented with a huge splenic ar- tery dissecting aneurysm that had been incidentally found and was successfully resected before rupture. The histopathologic findings were compatible with segmental mediolytic arteriopathy (SMA). Simultaneous involve- ment of the left renal and right common iliac artery was observed. The patient was also found to have an adrenocortical adenoma, gastrointestinal stromal tumor, hepatocellular carcinoma and schizophrenia. The rela- tionship between SMA and other accompanying diseases was discussed.
(Internal Medicine 42: 818-823, 2003)
Key words: segmental mediolytic arteriopathy, dissecting aneurysm, primary aldosteronism, gastrointesti- nal stromal tumor, hepatocellular carcinoma, schizophrenia
Introduction
Dissecting aneurysms of muscular splanchnic arteries of the abdomen are uncommon and the pathogenesis is poorly understood. Segmental mediolytic arteriopathy (SMA), for- merly called segmental mediolytic arteritis (1), is a rare nonatherosclerotic and nonvasculitic arteriopathy of un- known cause. SMA involves small to medium-sized intraab- dominal muscular arteries, or less frequently, intracranial, coronary and pulmonary arteries. SMA is considered to be one of the causes of sudden, catastrophic intraabdominal hemorrhage. Acute splenic artery dissection is rare and most cases are diagnosed after death, except for two surviving
cases (2, 3).
Here, we present a case of SMA in which the preoperative magnetic resonance (MR) angiography revealed multiple ab- dominal splanchnic artery aneurysms before rupture and suc- cessful surgical resection of the huge dissecting aneurysm of the splenic artery could be performed.
Case Report
A 46-year-old man was admitted to Nagasaki University Hospital on May 31, 2002 for the evaluation of an abdominal tumor, which was incidentally found by a cardiovascular sur- geon. In his family history, his father and elder brother had hypertension and his mother had uterus cancer. He was diag- nosed as having schizophrenia at the age of 29. Hypertension and hypokalemia due to primary aldosteronism (left adrenocortical adenoma) have been treated with spirono- lactone since 1999.
Physical examination on admission revealed an obese male (height, 168 cm; body weight, 84 kg), normal blood pressure (120/70 mmHg), pulse rate of 72 beats per minute and absolutely irregular. Examination of the heart, lungs and abdomen was unremarkable except for an upper abdominal tumor.
Electrocardiogram demonstrated chronic atrial fibrillation. The hematologic tests showed a hemoglobin of 11.2 g/dl, hematocrit of 36.1%, platelet count of 139,000/mm3, and white blood cell count of 3,600/mm3. Analysis of blood chemistry was as follows: total protein, 6.2 g/dl; albumin, 3.7 g/dl; thymol turbidity test (TTT), 15.9 kunkel; zinc sulfate turbidity test (ZTT), 13.0 kunkel; sodium, 146 mEq/l; potas- sium, 3.6 mEq/l; chloride, 110 mEq/l; calcium, 16 mg/dl; urea nitrogen, 12 mg/dl; creatinine, 1.0 mg/dl; asparate aminotransferase (AST), 33 IU/l; alanine aminotransferase (ALT), 39 IU/l; lactate dehydrogenase (LDH), 288 IU/l;
From the Division of Cardiovascular Medicine, *Division of Cardiovascular Surgery, Department of Translational Medical Sciences, Course of Medical and Dental Sciences, ** Division of Radiological Science, Department of Radiology, Course of Life Sciences and Radiation Research, Graduate School of Biomedical Sciences, Nagasaki University and *** Department of Pathology, Nagasaki University Hospital, Nagasaki Received for publication February 17, 2003; Accepted for publication May 8, 2003
Reprint requests should be addressed to Dr. Naoto Ashizawa, the Division of Cardiovascular Medicine, Department of Translational Medical Sciences, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8501
SMA in Splenic Arterial Dissecting Aneurysm
creatine phosphokinase (CPK), 85 IU/l. Serologically, the Wassermann reaction was negative. Elevated alpha- fetoprotein (AFP), 586.3 ng/ml and protein-induced by vita- min K absence II (PIVKA-II), 129 mAU/ml and hepatitis B virus (HBV) surface antigen (HBsAg), >x2,000 COI; HBV envelope antigen (HBeAg), 0.1 COI; anti-HBV envelope an- tibody (HBeAb) >x100, suggesting the existence of hepato- cellular carcinoma (HCC) associated with hepatitis B.
Abdominal enhanced computed tomography (CT) scan (Fig. 1) and MR angiography (Fig. 2) revealed a huge splenic artery aneurysm (7.5×9.5 cm, including mural throm- bus), an aneurysm in the middle portion of the left renal ar- tery (1.0 cm) and a fusiform right common iliac artery aneurysm (3.5 cm). No extravasation of contrast media was noted. Well enhanced tumors in right lobe of the liver, 4.0x 3.0 cm in diameter, and in the left adrenal gland, 2.5x3.0 cm in diameter were seen, suggesting the existence of HCC, and adrenal adenoma, respectively. A slightly enhanced tumor in the splenic hilum (3.5x2.5 cm in diameter) was also detected and diagnosed as a gastrointestinal stromal tumor (GIST), pathologically.
Since the huge splenic artery aneurysm had not ruptured
and the spleen was not infarcted, the patient underwent only the resection of the splenic artery aneurysm. Moreover there was no color change of the residual spleen, suggesting the existence of other feeding collaterals to the spleen; we did not perform splenectomy or reconstruction of the splenic ar- tery (Fig. 3). Histological examination disclosed the lesion to be a pseudoaneurysm of the splenic artery. However, neither atherosclerotic change nor vasculitis was observed. Dissec- tion of the medeia resulted in the formation of dissecting hematoma, causing the stenosis of the true lumen of the ar- tery (Figs. 4, 5). The segmental mediolysis of the media of the artery, which is the histopathological hallmark of SMA was observed at the proximal portion of the resected artery (Fig. 5). These findings were compatible with SMA. The tumor which was detected in the hilum of the spleen was also resected. The tumor originated from the body of the stomach, 3 cm in diameter. Histopathologically, the tumor consisted of a spindle cell proliferation in a fascicular or interlacing pat- tern. Mitotic activity was counted as 5 per 25 high power fields (HPF). The lesion was diagnosed as a GIST, uncom- mitted type because of the positive immunostaining for c-kit, CD 34 and vimentin, and negative staining for a smooth
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muscle actin and S100 protein. Transcatheter hepatic arterial embolization for the HCC was successfully performed, al- though selective catheterization to the hepatic artery via the true lumen was difficult since celiac to common hepatic ar- tery was also dissected and enlarged. The postoperative course of the patient was uneventful and he was discharged 2 weeks after surgery.
Discussion
SMA was first described as a distinct pathologic entity by Slavin and Gonzalez-Vitale in 1976 (1) and less than twenty cases involving abdominal splanchnic arteries have been re- ported in the literature (Table 1) (1, 3-13). Abdominal SMA occurs in the middle aged to elderly, ranging from 39 to 87 years, in both sexes. It usually involves more than one vis- ceral artery, and branches of the celiac axis are most fre- quently affected by SMA. Our case showed multiple aneurysms in celiac, splenic, left renal and right common iliac arteries and histopathologic examination of the resected splenic artery was compatible with SMA.
In the first report, Slavin and Gonzalez-Vitale thought the SMA was an immune complex arteritis and used the term “segmental mediolytic arteritis” (1). However, there are a
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few reports of SMA accompanied with autoimmune disease, such as systemic lupus erythematosus, microscopic polyarth- ritis nodosa (8, 10) and thus the immunologic etiology was abandoned, the term was changed to “segmental mediolytic arteriopathy” and they proposed that the arterial lesions of SMA were caused by vasospasm (4). Before the concept of SMA was proposed, the main pathological diagnoses of splenic artery dissection were cystic medial degeneration and fibromuscular dysplasia (2). Lie proposed that SMA was represented as a variant of fibromuscular dysplasia (14) and Slavin et al also suggested that the SMA might be a
Figure 5. A: Resected splenic artery aneurysm showing the dis- section of the media (arrows) and disruption of internal elastic lamina (arrowheads). The intima shows reactive fibrosis consist of myofibroblasts with myxoid matrix (Elastica-van Gieson stain, x25). B: Proximal portion of the resected artery wall shows multiple segmental mediolysis (arrowheads) (HE stain, ×50).
precursor lesion of fibromuscular dysplasia (9). Leu reported that the morphology of SMA resembles that of cystic medial necrosis of the aorta, which may occur in any muscular ar- tery (15). Although the pathogenesis of SMA remains con- troversial and the strategy for its treatment has not been established, in the present case, we decided to resect the an- eurysm because the size of the splenic artery aneurysm was huge and was most likely to rupture. Carr et al recommended operative treatment for splenic artery aneurysms greater than 2.5 cm (16). Recently only one case has been reported whereby coil embolization of SMA of the hepatic artery an- eurysm was performed (17); vascular intervention such as coil embolization or stent graft may be an option for the
| Age | Sex | Symptoms | Involved arteries | Complications | Outcome | Reference |
|---|---|---|---|---|---|---|
| 52 | M | IAH | Splenic, Colic (r, 1) | Pulmonary abscess | Autopsy | Slavin (1) |
| 80 | M | IAH | Pancreatico-duodenal, Splenic | Prostatic hypertrophy (p/o) | Autopsy | Slavin (1) |
| 73 | F | Abdominal pain Shock | Splenic, Gastro-duodenal, Cystic | Rupture of TAA | Autopsy | Slavin (1) |
| Gastro-epiploic (r, 1) Gastric (1) Pancreatico-duodenal, Colic (r), Renal | ||||||
| 87 | M | Abdominal pain | Jejunal | Alive | Slavin (4) | |
| 68 | M | IAH | Omental, Gastro-duodenal, Ileal, Renal | Heritz (5) | ||
| 75 | F | Abdominal pain | Hepatic | COPD | Alive | Armas (6) |
| 71 | F* | Abdominal pain | Gastric (1), Splenic | Mitral valve disease (p/o) | Autopsy Autopsy | Inayama (7) |
| Shock | ||||||
| 70 | F | IAH | Omental, Splenic, Pancreatic | SLE | Juvonen (8) | |
| 57 | F | Inferior mesenteric | Alive | Juvonen (8) | ||
| 64 | F | IAH | Colic (1) | COPD (a1 antitrypsin defi- | Alive | Slavin (9) |
| Shock | ciency) | |||||
| 66 | F | Rt hemiparesis | Hepatic | Meningioma (p/o) | Autopsy | Slavin (9) |
| Shortness of breath | ||||||
| 49 | F | IAH | Ileocolic | Myocardial infarction | Alive | Slavin (9) |
| Epigastric pain | Raynaud's phenomenon | |||||
| 73 | M* | Shock | Gastro-epiploic | Cerebral infarction, Hyperten- sion | Autopsy | Slavin (9) |
| 73 | M* | IAH, Shock | Splenic | Microscopic polyarthritis nodosa | Autopsy | Ito (10) |
| 57 | F* | IAH | Inferior mesenteric | Alive | Kato (11) | |
| 39 | M* | IAH, Shock | Hepatic, Colic | Autopsy | Nagashima (12) | |
| 67 | F | IAH, Shock | Hepatic, Splenic | Hypertension, Osteoarthritis | Alive | Chan (3) |
| 48 | M* | Stupor (SAH) Chest oppression | Vertebral (r), Internal carotid (1) | Autopsy | Sakata (13) | |
| Superior mesenteric, Renal (r, 1) External iliac (1) | ||||||
| 46 | M* | Abdominal tumor | Celiac, Splenic, Renal (1) | Adrenal adenoma (1), GIST HCC, Schizophrenia | Alive | Present case |
| Common iliac (r) |
IAH: intraabdominal hemorrhage, SAH: subarachnoid hemorrhage, TAA: thoracic aortic aneurysm, COPD: chronic obstructive pulmo- nary disease, SLE: systemic lupus erythematosus, GIST: gastrointestinal stromal tumor, HCC: hepatocellular carcinoma, p/o: post opera- tive, 1: left, r: right, *: Japanese patient.
treatment of SMA.
Incidentally, a simultaneous gastric mass was also found in this patient. It was histologically identified as cellular spindle cell tumor and characteristically expressed c-kit and CD 34, which were consistent with GIST, uncommitted type. Since the mitotic counts exceeded 5 per 50 HPF, and the subtype was uncommitted type, this tumor was thought to be malignant, although the size was smaller than 5 cm (18). The existence of HCC and adrenal adenoma was strongly sug- gested by clinical and radiological examinations, though it was not confirmed histopathologically. The relation of these coexisting diseases and multiple splanchnic artery aneurysm is unclear and it might be impossible to explain that these various diseases originate monogenetically. However, from the embryological point of view, smooth muscle cells, adre- nal cortex and GIST are mesodermally derived and an abnor- mality of mesodermal development or differentiation might be related to the pathogenesis of SMA.
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SMA in Splenic Arterial Dissecting Aneurysm
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