Normal Spleen Size in Adults
The normal spleen size in adults is defined as ≤13 cm in vertical length when measured in the coronal plane on imaging studies. 1
Standardized Measurement Parameters
The spleen should be measured as vertical length in the coronal plane, which is the gold standard approach recommended by major medical societies. 1 This measurement can be obtained through:
- CT scan: Measure vertical length directly on coronal images 1
- Ultrasound: Obtain coronal view including the hilum during quiet breathing 2
- PET/CT: Measure splenic coronal diameter on maximum intensity projection images 1
The 13 cm threshold is the universally accepted cutoff established in the Lugano Classification and RECIL 2017 criteria, and is applied across all clinical contexts. 3
Clinical Grading System
Understanding the spectrum of spleen size helps guide clinical decision-making:
- Normal: ≤13 cm in length 1
- Mild splenomegaly: 11-13 cm 1, 3
- Clinically significant splenomegaly: >13 cm 1, 3
- Severe splenomegaly: ≥5 cm below left costal margin (particularly concerning when >15 cm below costal margin) 3
Important Clinical Considerations and Pitfalls
Physical examination alone is unreliable for detecting splenomegaly, making imaging essential for accurate assessment. 1 This is a critical pitfall that can lead to missed diagnoses.
A normal-sized spleen does not exclude splenic pathology. 1 The spleen may be normal in size but still harbor lymphoma or other infiltrative processes. 4, 1 Conversely, an enlarged spleen may reflect benign causes rather than disease. 4, 1
Spleen size varies based on multiple factors including race, body size, height, sex, and blood volume status. 1, 2 Males typically have larger spleens than females (mean 10.68 cm vs smaller dimensions). 2 Height and weight show stronger correlations with spleen volume than age or BMI. 2
Non-pathological causes of enlargement must be considered, including variations in blood volume, use of hematopoietic growth factors, or anatomical variations. 4, 1 These can confound clinical interpretation.
Practical Application in Lymphoma and Hematologic Disease
In lymphoma staging and response assessment, splenomegaly is specifically defined as >13 cm vertical length. 1 For complete remission criteria, the spleen must not be palpable on examination and should measure normal size on imaging, with lymphoma-related nodules disappeared. 4
However, determination of splenic involvement is not always reliable because normal-sized spleens may contain lymphoma while enlarged spleens may have non-malignant causes. 4 This underscores why imaging findings must be interpreted within the full clinical context rather than in isolation. 3