Polysplenia syndrome

Polysplenia syndrome, also known as left isomerism, is a type of heterotaxy syndrome where there are multiple spleens congenitally as part of left-sided isomerism.

Polysplenia is seen predominantly in female patients. It is usually diagnosed in childhood or adulthood, later than asplenia syndrome, since associated congenital heart diseases tend to be less severe than those encountered in the latter.

The exact cause of polysplenia is unknown. However it is suggested that it is caused by various factors 10:

  • embryogenic
  • genetic
  • teratogenic 

Clinical presentation is related to the associated pathology.

Polysplenia results from failure of development of the usual left-right asymmetry of organs and consists of situs ambiguus, with features of bilateral left-sidedness.

It is characterized by multiple splenules without a parent spleen. It occurs on the patient’s left side but may be bilateral. The most common associated feature is inferior vena cava interruption with azygos or hemiazygos continuation 3.

Other characteristic features include:

Anatomy: Abdominopelvic
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Article information

rID: 21610
Section: Syndromes, Anatomy
Synonyms or Alternate Spellings:
  • Left isomerism
  • Polysplenia
  • Bilateral left-sidedness
  • Left sided isomerism

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Cases and figures

  • Case 1
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  • Case 2 : with azygous continuation of the IVC
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  • Case 3 : with multiple spleens of variable size
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  • Case 4
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  • Case 5 : situs inversus abdominalis
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  • Case 6
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