What are the causes of splenic granulomas?

From the Guidelines

Splenic granulomas are most commonly caused by infections, such as histoplasmosis, tuberculosis, and other fungal infections, as well as sarcoidosis, a multisystem inflammatory disorder of unknown etiology. The causes of splenic granulomas can be diverse, including:

• Infections: histoplasmosis 1, tuberculosis, and other fungal infections
• Sarcoidosis: a multisystem inflammatory disorder of unknown etiology 1
• Autoimmune conditions: rheumatoid arthritis and systemic lupus erythematosus
• Medications: sulfonamides, phenytoin, and allopurinol can trigger drug-induced granulomatous reactions
• Foreign body reactions, lymphomas, and other malignancies
• Occupational exposures: berylliosis, silicosis, or other occupational exposures 1

Diagnosis of splenic granulomas typically requires imaging studies like CT or MRI, with definitive diagnosis often necessitating histopathological examination through spleen biopsy or splenectomy 1. Treatment should focus on addressing the underlying cause rather than the granulomas themselves, with antimicrobial therapy for infections, immunosuppressants for autoimmune conditions, or discontinuation of offending medications in drug-induced cases. According to the most recent guidelines, asymptomatic patients with certain noninfectious complications or residue of healed histoplasmosis, such as asymptomatic pulmonary nodules, mediastinal lymphadenopathy, and splenic lesions, especially when calcified, do not require treatment 1.

From the Research

Causes of Splenic Granulomas

• Splenic granulomas can be caused by various factors, including:
  • Sarcoidosis, a multisystem granulomatous disease of unknown cause 2, 3
  • Infections, such as tuberculosis 4
  • Latent infection of Propionibacterium acnes, which can cause sarcoidosis 5
  • Hypersensitivity pneumonias, caused by exogenous microorganisms 5
• The formation of granulomas is a chronic inflammatory reaction involving macrophages and other inflammatory cells, which can be triggered by antigen exposure and processing 5
• The causes of splenic granulomas can be classified into infectious and non-infectious granulomas, although it can be difficult to differentiate between the two 5, 4
• In some cases, the cause of splenic granulomas may be unknown, and diagnosis may require biopsy or splenectomy 3

Types of Granulomas

• Non-caseating granulomas, characteristic of sarcoidosis 2, 3
• Caseating granulomas, characteristic of tuberculosis 4
• Necrotizing sarcoid granuloma, a variant of sarcoidosis that can make it difficult to differentiate from other infectious processes 6

Diagnosis and Challenges

• Diagnosis of splenic granulomas can be challenging, especially in areas with a high burden of tuberculosis 4
• Imaging techniques, such as computed tomography and magnetic resonance imaging, can be useful in evaluating splenic lesions, but may not be specific for diagnosis 3
• Biopsy or splenectomy may be necessary for definitive diagnosis 3