Renal arterial aneurysm--an incidental finding at autopsy.

P Vaideeswar, CV Madiwale 
 Department of Pathology, Seth G.S. Medical College, Mumbai.

Correspondence Address:
P Vaideeswar
Department of Pathology, Seth G.S. Medical College, Mumbai.

Full Text

::   Introduction

Renal arterial aneurysms represent an unusual renovascular disease. They can affect the main renal arteries or its branches or can even be intraparenchymal. We report a renal artery aneurysm affecting the left kidney with an unusual morphology, seen as an incidental finding at autopsy.

::   Case report

A 50-year-old woman was admitted in a gasping state following left sided chest pain. She was a hypertensive on irregular treatment. Despite resuscitative measures, she died within an hour of admission.

A complete autopsy was performed. At autopsy, both her kidneys were small in size (70 gm each) with a finely granular cortical surface. An interesting finding was the presence of a small 'cauliflower florette' like exophytic mass over the lateral convexity of the left kidney. It measured 1.5 cm in diameter. On bisection, the mass had a corrugated, startlingly white and calcific periphery and a soft, gelatinous yellowish white centre [Figure:1]. The cortex was markedly thinned out in both kidneys.

On histology, the mass was seen in relation to an interlobar artery. It had a fibrous, calcified wall and lumen occluded by recanalized thrombus [Figure:2]. a diagnosis of renal artery aneurysm was made. Twisted and fragmented twigs of elastic fibres could be demonstrated by elastic van Geison stain. Both kidneys revealed benign nephrosclerosis, with marked arterial changes.

Cause of death was related to acute myocardial infarction secondary to critical narrowing of the left anterior descending artery.

::   Discussion

Renal artery aneurysms have been previously considered to be rare with an incidence ranging from 0.015 to 9.7%[1]. But these are not diagnosed more frequently in recent years due to use of visceral angiography for evaluation of hypertension and peripheral vascular disease.

Aneurysms of the renal artery have been classified as saccular, fusiform, dissecting and intrarenal[2]. In a large series of cases by Martin et al1 and Ortenberg et al[3], they found that these aneurysm are found at the bifurcation of the main renal artery or its branches, related to atherosclerosis, hypertension, fibromuscular dysplasia, arteritis, trauma and in children in association with neurofibromatosis. On the other hand, intrarenal aneurysms may be saccular or fusiform. The causes include those mentioned above along with trauma or damage following kidney biopsy and renal carcinoma. Patients are usually elderly and asymptomatic. Others present with hypertension, flank pain or haematuria. We found a saccular aneurysm in an elderly and hypertensive woman. The relationship of renal artery aneurysms with hypertension is still controversial. Majority believe that aneurysms are a result of hypertension[4] and only rarely produce hypertension[1].

The peculiar morphology of the saccular aneurysm in the reported case was produced due to shrinkage of the renal parenchyma consequent to benign nephrosclerosis. This resulted in the saccular aneurysm of interlobar artery to project from the cortical surface. Calcification is a usual feature[5] but thrombotic occlusion is rare[6].

The current trend in therapy of such aneurysms is to limit indications for surgery to certain specific cases (rupture, large size and cause of hypertension) since risk of rupture is small[7].

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