Splenic Mass

Daniel J. Podberesky, MD

DIFFERENTIAL DIAGNOSIS

Common

Perfusion Artifact
Trauma
Granulomatous Disease
Lymphoma
Acquired Cyst
Hematoma
Infarction
Infection and Abscess

Less Common

Congenital Cyst
Metastases
Primary Tumor

Rare but Important

Post-Transplant Lymphoproliferative Disease
Lymphatic Malformation

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Primary and metastatic splenic malignancies are rare in children, except for lymphoma and leukemia
Clinical history is crucial as many splenic lesions have similar imaging characteristics
- Is child immunocompromised?
- Is there known primary neoplasm?
- Does patient have sickle cell disease or other hemoglobinopathy?
- Is there history of trauma?

Helpful Clues for Common Diagnoses

Perfusion Artifact
- Seen during arterial phase of CT and MR
- Patterns include striped, focal, and diffuse heterogeneity
- Ultrasound helpful in difficult cases
- Hint: Resolves on delayed phase imaging (> 70 sec)
Trauma
- Trauma history is helpful
- Laceration, fracture, rupture all possible
- Splenic injury more common when spleen is enlarged, i.e., with infectious mononucleosis
- Active bleeding manifests as foci of high attenuation
- American Association for the Surgery of Trauma grading system
  - Grade 1: Subcapsular hematoma, < 10% surface area OR < 1 cm deep laceration
  - Grade 2: Subcapsular hematoma, 10-50% surface area OR 1-3 cm laceration not involving parenchymal vessel
  - Grade 3: Subcapsular hematoma, > 50% surface area or expanding/ruptured, OR parenchymal hematoma > 5 cm OR laceration > 3 cm
  - Grade 4: Laceration of vessel producing devascularization of > 25% of spleen
  - Grade 5: Shattered spleen OR hilar vascular injury
Granulomatous Disease
- Old granulomatous disease (such as histoplasmosis) frequently demonstrates small calcified splenic lesions
- Wegener granulomatosis may involve spleen
- Sarcoidosis may involve spleen
Lymphoma
- Hodgkin or non-Hodgkin lymphoma can involve spleen
- Focal lesions or diffuse involvement
- Typically hypoattenuating on CT and hypoechoic on US
- Hint: Look for associated lymphadenopathy
Acquired Cyst
- Pseudocysts (lack epithelial lining)
- Typically result from prior trauma, infarct, or infection
- Differentiation by imaging from congenital cyst not reliable
Hematoma
- Typically secondary to trauma
- May be parenchymal or subcapsular
- May lead to acquired splenic cyst
Infarction
- Secondary to occlusion of noncommunicating end arteries of spleen
- Commonly seen in children with hemoglobinopathies, such as sickle cell disease, and malignancies
- Variable appearance depending on stage
  - Early: Ill-defined mottled changes in density on CT or echogenicity on US
  - Late: Well-defined peripheral hypoechoic or hypodense wedge-shaped regions
- May resolve completely or evolve into acquired cyst
Infection and Abscess
- Fungal and bacterial infections occur most frequently in immunocompromised patients
- Fungal splenic abscesses are hypodense and typically small
  - Hint: Look for lesions in liver, kidneys, and lungs as well
- Hydatid abscesses are rare

Helpful Clues for Less Common Diagnoses

Congenital Cyst
- True cyst (epithelial lining)
- Includes epidermoid cysts and mesothelial cysts
- Differentiation by imaging from acquired cyst not reliable
Metastases
- Splenic metastases are rare
  - Hint: Look for metastases in other visceral organs
- Melanoma
- Variable imaging appearance
  - Typically hypoechoic/hypodense relative to normal spleen
  - Can see cystic splenic metastases
Primary Tumor
- Malignant
  - Majority lymphoma and leukemia
- Benign hamartoma
  - Nonneoplastic mixture of normal splenic components
  - Can be seen in tuberous sclerosis patients with hamartomas in other organs
  - Nonspecific imaging appearance, occasionally with calcifications
- Benign hemangioma
  - Most common primary splenic neoplasm
  - Can be solitary or multiple
  - Can cause Kasabach-Merritt syndrome (thrombocytopenia and consumptive coagulopathy)
  - Variable imaging appearance

Helpful Clues for Rare Diagnoses

Post-Transplant Lymphoproliferative Disease
- Complication of solid organ transplant and allogeneic bone marrow transplant
- Associated with EBV infection
- Spleen involved in ˜ 20% of cases
- Similar imaging appearance to lymphoma
- Hint: Look for involvement of other organs
  - Lymph nodes
  - Liver
  - Lung
  - CNS
Lymphatic Malformation
- Nonneoplastic endothelial-lined lymph channels
- Septate cystic lesions most commonly
- May contain debris or fluid-fluid levels
- Septa and rim typically enhance

Image Gallery

Coronal CECT shows heterogeneous stripes of low attenuation in the spleen, a common normal variant seen during arterial phase imaging. This pattern has been referred to as “tiger” or “zebra” striped.