From the Research
The presence of a splenule, a small accessory spleen, can provide some immune protection in individuals without a functioning main spleen, but it is crucial to prioritize vaccination against encapsulated bacteria to reduce the risk of infection, as recommended by the most recent study 1. When comparing the spleen and splenule, it's essential to consider their functions and implications for patient care. The spleen is a vital organ that filters blood and helps fight infections, whereas splenules are smaller nodules of splenic tissue that develop during embryonic development.
- Splenules are typically found near the main spleen, often around the splenic hilum or along the splenic vessels, but can occasionally be found in other locations like the pancreas tail or greater omentum.
- They occur in about 10-30% of the population and usually measure less than 2 cm in diameter.
- Splenules perform the same immunological and hematological functions as the main spleen but on a smaller scale.
- They generally cause no symptoms and are often discovered incidentally during imaging or surgery. Their clinical significance emerges primarily after splenectomy, as remaining splenules can grow in size (compensatory hypertrophy) and potentially maintain some splenic function, which can be beneficial for immune protection but problematic if the splenectomy was performed for conditions like certain anemias or thrombocytopenias, as noted in studies 2, 3. In terms of management, vaccinations against S. pneumoniae, N. meningitidis, H. influenzae type b, and influenza virus are strongly recommended for individuals with a splenule or without a functioning main spleen, as emphasized by the most recent and highest quality study 1. It's also important to consider the diagnostic challenges posed by splenules, which can resemble neoplastic processes on imaging studies, and the role of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in recognizing splenules and avoiding unnecessary surgical management, as discussed in a recent study 4.