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Splenomegaly

Last revised by Dr Joachim Feger on 28 Nov 2021

Splenomegaly refers to the enlargement of the spleen. The upper limit of the normal adult splenic length is traditionally cited at 12 cm, but lengths upwards of 14 cm can be seen in normal, taller males 7.

Massive splenomegaly is variably defined, including when the spleen is 5 standard deviations above the mean normal volume (about 943 cm34, heavier than 1.0 kg 5 or 1.5 kg 8, longer than 18 cm 8, or extending into the pelvis or across the midline 4.

The causes of splenomegaly are protean, and can be thought of under several headings 3,8:

  • hematological disease
  • hemodynamic
  • infectious
  • storage diseases/metabolic/infiltrative disorders
  • neoplastic (non-hematologic)
  • traumatic
  • connective tissue disorders

* may cause massive splenomegaly 3,8

The shape and orientation of a spleen make accurate linear measurement difficult.

On CT, a splenic width measurement (largest anterior-posterior measurement on axial images) of greater than 10.5 cm is the most accurate single measurement for mild to moderate splenomegaly in patients with cirrhosis; while a craniocaudal measurement of greater than 14.6 cm is the most accurate single measurement for massive splenomegaly 4.

On sonographic assessment, a length of 12 cm is generally considered the upper limit of normal. 

Since single caliper measurements are relatively inaccurate many volume-based approaches have been proposed. True volumetry is the most accurate but is rarely feasible in routine clinical practice. For cross-sectional imaging, the splenic index was first proposed to express splenic volume 10

The index can be calculated with the following formula 

Splenic index = length × width × thickness (cm)

The originally proposed normal range of the index is 120-480.

Since the index does not have a dimension other formulas were proposed for estimating splenic volume on cross-sectional imaging 5

Spleen volume (cm3) = 30 + 0.58 × craniocaudal length × diameter × thickness (cm)

Where:

  • length is defined as the craniocaudal distance between the first and last slices in the axial plane where the spleen is depicted
  • diameter is the largest measurable long axis distance in the axial plane
  • thickness is the largest perpendicular dimension to the diameter in the axial plane

The normal range of the estimated volume in healthy individuals with this formula is: 107.2 – 314.5 cm3 (mean: 214.6 cm3)

On ultrasound even today the prolate ellipsoid formula is used most commonly 13

Spleen volume (cm3) = 0.52 × length × anteroposterior dimension × width (cm)

A modified formula was also proposed to improve accuracy 14

Spleen volume (cm3) = 0.524 × width × thickness × (maximum length + craniocaudal length) / 2

The normal spleen size for any individual is substantially influenced by demographic factors, gender, and body habitus. E.g. a study using volumetry found a 236.89 ± 77.58 cm3 average normal spleen size, whilst thresholds of 314.47 and 430.84 cm3 were determined for mild and massive splenomegaly respectively 11. In contrast, a study done by Japanese researchers has found much lower values in a different patient population for average spleen volume (112 cm3) and normal range (32-209 cm3) 12. Furthermore, it has been also shown that normal spleen size is influenced by sex and body habitus, with men, and taller or heavier individuals having longer and larger spleens 13

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Cases and figures

  • Figure 1: splenic deposits in CLL
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  • Case 1
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  • Case 3
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  • Case 2
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  • Case 4 : with splenic infarct
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  • Case 5 : CML with splenic Infarction
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  • Case 6 : CML with massive splenommegaly
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  •  Case 8 : lymphoma
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  • Case 9: myelofibrosis
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  • Case 10: on abdominal x-ray
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  • Case 11: with sickle cell disease
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  • Case 12: with leukemia
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  • Case 13: Lymphoma: Lugano classification
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  • Case 14 : Gaucher disease
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  • Case 16
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  • Case 15 : Wilson's disease and cirrhosis
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  • Case 17
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  • Case 18: infectious mononucleosis
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