Diagnosis
Heterotaxy syndrome with polysplenia </<span class="end-tag" />P
Findings
Multiple visceral anomalies were incidentally discovered on the CT
of the chest and the upper abdomen, which was performed for chest
pain. There was a midline liver, right-sided stomach, polysplenia
in the right upper quadrant posterior to the stomach, and inferior
vena cava (IVC) interruption with azygos continuation (Figures 1
and 2A). Each spleen ranged in size from 2 to 3 cm. No spleen was
noted in the left upper quadrant. A dilated azygos vein drained
into the superior vena cava (SVC). There was a persistent left SVC
(Figures 1B, 1C, and 2B) that emptied into the coronary sinus
(Figure 2B). Both main pulmonary trunks coursed over the main stem
bronchi (Figures 1C, 1D, and 3A), representing the characteristic
bilateral hyparterial bronchial pattern seen in this syndrome. Both
lungs were bilobed. Each main stem bronchus branched in a
left-sided pattern into an upper- and lower-lobe bronchus (Figure
3B). </<span class="end-tag" />P
Discussion
Heterotaxia, or situs ambiguous, indicates visceral dysmorphism.
This is an abnormal arrangement of organs and vessels in the chest
and abdomen.<
Sup>1
</<span class="end-tag" />Sup>The 2 main subtypes of
situs ambiguous are situs ambiguous with polysplenia and situs
ambiguous with asplenia.<
Sup>2
</<span class="end-tag" />Sup></<span
class="end-tag" />P
><
P
>Heterotaxia with polysplenia, also known as <
I>left isomerism </<span
class="end-tag" />I>or <
I>bilateral left-sidedness</<span
class="end-tag" />I>, is characterized by a midline or
ambiguous location of the majority of chest and abdominal viscera,
multiple spleens, and an absence of some right-sided structures,
such as the IVC.<
Sup>2
</<span class="end-tag" />Sup>Although there is great
variability in the spectrum of abnormalities and no single anomaly
that is pathognomonic for this disorder, IVC interruption with
azygos continuation is the most common &
#64257;nding.<
Sup>1 </<span class="end-tag"
/>Sup>The syndrome is characterized by bilateral bilobed
left-sided lungs and hyparterial bronchial pattern, intrahepatic
IVC interruption with continuation of the azygos vein, a centrally
located transverse liver, a stomach in an indeterminate position,
and multiple spleens, all of which were present in our patient. The
spleens vary in size and number, but are always on the same side as
the stomach.<
Sup>1
</<span class="end-tag" />Sup>While 99% to 100% of the
patients with situs ambiguous and asplenia have congenital heart
diseases, cardiac anomalies are less common in polysplenic patients
(50% to 90%).<
Sup>3
</<span class="end-tag" />Sup>They are also often not
as complex, which explains their survival into adulthood.<
Sup>1,2 </<span class="end-tag"
/>Sup>In our patient, the only cardiac abnormalities were a
persistent left SVC draining into the coronary sinus, a persistent
foramen ovale, and a bicuspid aortic valve (not shown).
</<span class="end-tag" />P
><
P
>Other gastrointestinal abnormalities associated with
polysplenia include biliary atresia, intestinal malrotation, and
truncated pancreas (only the pancreatic head or body is present).
Neither abdominal heterotaxy nor multiple spleens need not always
be present. The stomach and cardiac apex are discordant in roughly
50% of cases.<
Sup>2
</<span class="end-tag" />Sup>The clinical
presentation, morbidity, and mortality are usually related to the
presence and severity of cardiac defects, biliary atresia, or bowel
malrotation. </<span class="end-tag" />P
><
P
>Although heterotaxy and polysplenia in most adult
patients is asymptomatic and is detected incidentally, the role of
radiologists in recognizing the complex anatomy is crucial in the
clinical setting. The presentation of an acute abdomen in these
patients can be confusing because the pain from acute
cholecystitis, appendicitis, or other pathology is often not at the
usual location.<
Sup>2
</<span class="end-tag" />Sup>Similarly, the imaging
appearance can be perplexing if the radiologist is not aware of the
spectrum of &
#64257;ndings
associated with these syndromes. </<span class="end-tag"
/>P
><
p><
B>CONCLUSION </<span
class="end-tag" />B></<span class="end-tag"
/>p><
P
>Heterotaxia or situs ambiguous with polysplenia is a
rare spectrum of congenital abnormalities involving the visceral
organs and cardiovascular structures in the chest and abdomen. The
knowledge and recognition of the complex and often confusing
anatomy of these patients is important in diagnosing pathology and
planning appropriate surgical, diagnostic, and interventional
procedures. </<span class="end-tag" />P
<
OL
type=
"1"
><
LI
>Applegate KE, Goske MJ, Pierce G, Murphy D. Situs
revisited: Imaging of the heterotaxy syndrome. RadioGraphics.
1999;19:837-852; discussion 853-854. </<span class="end-tag"
/>LI
><
LI
>Fulcher AS, Turner MA. Abdominal manifestations of situs
anomalies in adults. RadioGraphics. 2002;22:1439-1456.
</<span class="end-tag" />LI
><
LI
>Tonkin IL. The de&
#64257;nition of cardiac malpositions with
echocardiography and computed tomography. In: Friedman WF, Higgins
CB, eds. Pediatric Cardiac Imaging. Philadelphia, PA: Saunders;
1983;157-187. </<span class="end-tag" />LI
></<span class="end-tag" />OL
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