Splenule (Accessory Spleen)

Splenules are nodules of splenic tissue that you are born with.  They are common on imaging studies.  Splenules rarely cause complications.   They can be diagnosed confidently on imaging studies.

It is important to recognize splenules in patients who are undergoing removal of the spleen.  It is also important to not confuse a splenule for an abnormality like a lymph node or cancer.

What is a splenule?

Splenules are also called an accessory spleen.  They are nodules of splenic tissue that you are born with.  Many are small splenules measuring under 2 cm.

Splenule symptoms

Splenules do not have symptoms since they are normal structures in the body.  In very rare cases, splenules may twist on themselves (torsion), bleed, or develop infarctions.

Intrapancreatic splenule

One of the characteristic locations for splenules is within the pancreas itself.  This is most common in the tail, or the part of the pancreas closest to the spleen.  The nodule of splenic tissue can mimic a tumor of the pancreas.

Multiple splenules

Splenules are often multiple in number.  Multiple splenules is also a normal finding in the body.  They represent multiple nodules of splenic tissue.

Splenules after splenectomy

The main concern of splenules after splenectomy is that they can cause disease recurrence.  Splenules need to be removed with the spleen.

Splenule in the splenic hilum

Splenic hilum is where the blood vessels enter and leave the spleen.  This is one of the most common locations for a splenule.

How is a splenule diagnosed?

A splenule is diagnosed on imaging studies like ultrasound, CT, MRI and nuclear medicine studies.

What does a splenule look like on imaging?

A splenule will closely follow what the spleen looks like on all imaging tests.  An MRI is best for cases that are not certain.  MRI will show a splenule to look like the spleen on all the imaging sequences obtained.  CT can also help diagnose a splenule when done in multiple phases.

What else can look like splenule in radiology?

Splenules are nodules outside of the spleen.  They can be located in multiple locations around the spleen in the left upper abdomen.

Splenules can be confused for enlarged lymph nodes.

Splenules can mimic spread of cancer or tumors.  For example, they can occur in the pancreas and mimic a tumor.  They can also present at the site of a kidney removal and mimic a cancer recurrence.

What causes a splenule?

Splenules form during embyogenesis.  Failure of fusion of the components of the spleen may lead to a splenule.

Is a splenule dangerous?

No.  It is a normal structure in the body.  Splenules can very rarely have complications like torsion or bleeding.

Splenule treatment

Splenules are not treated.  They are normal structures in the body.  Treatment is only needed in the rare case that there is a complication.

Splenule: summary

Splenules are nodules of normal splenic tissue you are born with.  They are common on imaging studies.  They can rarely be confused for lymph nodes or tumors.  Imaging studies like CT and MRI often make a confident diagnosis.  Splenules do not need treatment unless there is a rare complication like torsion or bleeding.