Cardiovascular Journal of Africa: Vol 27 No 1 (January/February 2016)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 1, January/February 2016 AFRICA 49
Intimomedial mucoid degeneration causing aortic and
renal artery aneurysms in a young adult
Charle Viljoen, Patryk Szymanski, Naeem Osman, Kristin Lorenc Henning, Paul Scholtz, Brian Rayner,
Nadraj Naidoo
Abstract
Intimomedial mucoid degeneration (IMMD) is characterised
by aneurysm formation following mucin deposition in the
intima and media, with elastic tissue degeneration of the arte-
rial wall. We present a case of a young adult who developed
a diffusely aneurysmal aorta and its major branches, which
was histopathologically confirmed as intimomedial mucoid
degeneration, and a review of the literature. This case report
attempts to raise the awareness of the reader to this rare cause
of aortic aneurysm and to the bleeding diathesis associated
with IMMD that may complicate surgery.
Keywords: intimomedial mucoid degeneration, aortic aneurysm,
dissection
Submitted 25/2/15, accepted 4/10/15
Cardiovasc J Afr 2016; 27: 49–52
DOI: 10.5830/CVJA-2015-079
Intimomedial mucoid degeneration (IMMD) is a rare vascular
disorder characterised by the deposition of mucin in the intima
and media, which leads to elastic tissue degeneration and
aneurysm formation of the arterial wall.1-4 Although the condition
was initially thought to involve only the aorta, subsequent
publications have reported IMMD to affect the major branches
of the aorta, as well as smaller vessels such as the coronary and
brachial arteries.1,5,6-8 The aneurysms in IMMD usually have a
saccular or fusiform morphology and cause symptoms related to
the location of the aneurysm.6,8
Surgery is often complicated by a bleeding diathesis distinct
from disseminated intravascular coagulation (DIC), but
which resolves after surgical treatment of the diseased vessel.2
Meticulous surgical technique is of paramount importance.2,6
Peri-operatively, the coagulation profile and platelet function
should be carefully monitored and diligently corrected.
Case report
A healthy 18-year-old male presented to the emergency unit with
a two-week history of coughing with increasing dyspnoea and
a feeling of ‘heaviness on the chest’. On examination, a blood
pressure measurement of 177/105 mmHg was noted, with good-
volume regular pulses that were equal and present throughout,
with no bruits. The jugular venous pressure was not elevated
and the apex was undisplaced. Heart sounds were normal, but
auscultation of the chest revealed crackles in the lung bases. A
pulsatile mass was palpated in the epigastrium.
The admission chest radiograph revealed pulmonary oedema
and a widened mediastinum (Fig. 1), with the lateral film
confirming dilatation of the descending thoracic aorta. Blood
work returned with Na 142 mmol/l, K 4.7 mmol/l, urea 15.7
mmol/l and creatinine 306 μmol/l. The white blood cell count
was 16.82 × 109 cells/l, haemoglobin 8.7 g/dl, mean cell volume
72.4 fl and platelets 338 109 cells/l. The C-reactive protein (CRP)
was 210 mg/l and erythrocyte sedimentation rate (ESR) was 111
mm/h. HIV and syphilis serology returned negative.
A computerised tomographic angiogram (CTA) showed that
the descending thoracic aorta was aneurysmal throughout its
course (maximum diameter 46 mm), with multiple complex
dissection flaps (Fig. 2). The abdominal aortawas alsoaneurysmal
with a large lobulated aneurysm below the level of the superior
mesenteric artery (maximum diameter of 52 mm). The diseased
aorta was diffusely thick walled with no calcification. Both
renal arteries arose from the lobulated aneurysm and the left
renal artery origin was noted to be aneurysmal (Fig. 3). There
was poor contrast filling within both renal arteries proximally,
likely related to dissection. Further aneurysms involved the right
subclavian, left common carotid and right superficial femoral
arteries.
An echocardiogram showed mildly impaired left ventricular
function, but normal valves. A DMSA scan indicated a
differential glomerular filtration rate of 4 ml/min and 15 ml/min
to the right and left kidney respectively.
In spite of optimal blood pressure management, his
renal function continued to decline. Haemodialysis was
commenced prior to staged repair of a complex type 2 thoraco-
abdominal aneurysm. The first stage involved a left renal
auto-transplantation. Histology of the left renal artery, as
demonstrated in Figs 4, 5 and 6, showed mucin accumulation
within the intimal and medial layers with disruption of the elastic
Department of Medicine, Groote Schuur Hospital and
University of Cape Town, South Africa
Charle Viljoen, MB ChB, MMed, FCP (SA),
Patryk Szymanksi, MB ChB
Division of Anatomical Pathology, National Health
Laboratory Service, Groote Schuur Hospital and University
of Cape Town, South Africa
Naeem Osman, MB ChB, FC Path (SA) (Anat)
Division of Radiology, Groote Schuur Hospital and
University of Cape Town, South Africa
Kristin Lorenc Henning, MB ChB, DCH, FC Rad Diag (SA)
Paul Scholtz, MB ChB, MMed, FC Rad Diag (SA)
Division of Nephrology and Hypertension, Groote Schuur
Hospital and University of Cape Town, South Africa
Brian Rayner, MB ChB, FCP, MMed, PhD
Division of Vascular Surgery, Groote Schuur Hospital and
University of Cape Town
Nadraj Naidoo, MB ChB, FCS (SA)