Can a splenule (small accessory spleen) cause pain?

Can Splenules Cause Pain?

Yes, splenules (accessory spleens) can cause pain, particularly when they undergo torsion, infarction, or other pathological processes that affect normal splenic tissue.

Understanding Splenules

Splenules, also known as accessory spleens, are small nodules of splenic tissue that are separate from the main spleen. They are found in approximately 10-30% of the population and are typically located near the splenic hilum or in the peripancreatic region.

Key characteristics:

• Usually 1-2 cm in diameter
• Similar tissue composition to the main spleen
• Most commonly found near the splenic hilum, tail of pancreas, or splenic vessels
• Usually asymptomatic when normal

Pathological Processes That Can Cause Pain in Splenules

1. Torsion

Splenules can undergo torsion (twisting) around their vascular pedicle, leading to:

• Acute abdominal or left-sided chest pain
• Potential vascular thrombosis and infarction
• Symptoms resembling those of splenic torsion 1

2. Infarction

When blood supply to a splenule is compromised, infarction can occur, causing:

• Localized pain in the left upper quadrant
• Referred pain to the left shoulder
• Symptoms similar to splenic infarction as seen in endocarditis patients 2

3. Enlargement/Hypertrophy

After splenectomy, remaining splenules may enlarge and become symptomatic:

• Particularly in patients with hematologic disorders (ITP, autoimmune hemolytic anemia)
• Can cause recurrence of the original disease symptoms 2, 3

4. Trauma

Splenules can be injured during procedures or trauma:

• May cause pain similar to splenic injury
• Has been reported as a complication of procedures like colonoscopy 4

Diagnosis of Symptomatic Splenules

Imaging Studies:

• Ultrasound: Shows round or oval solid structures with echogenicity similar to the main spleen 5
• CT/MRI: High sensitivity (90-95%) for detecting splenules and associated complications 2
• Nuclear medicine scans: Can identify functional splenic tissue using radiolabeled heat-damaged erythrocytes 3
• Endoscopic ultrasound-guided FNA: Can confirm splenic tissue when diagnosis is uncertain 6

Key diagnostic features:

• Similar tissue density to the main spleen on imaging
• Blood supply from splenic artery or vein (visible in 90% of cases) 5
• Characteristic cytological features if FNA is performed 6

Management of Symptomatic Splenules

Conservative management:

• Appropriate for asymptomatic or mildly symptomatic splenules
• Monitoring with serial imaging

Surgical intervention:

• Indicated for:
  • Severe pain
  • Torsion
  • Infarction
  • Recurrence of hematologic disease after splenectomy 2, 3

Post-splenulectomy considerations:

• If all functional splenic tissue is removed, vaccination against encapsulated organisms is recommended (S. pneumoniae, H. influenzae, N. meningitidis) 2

Clinical Pearls and Pitfalls

Pearls:

• Consider splenule pathology in patients with unexplained left upper quadrant pain, especially those with prior splenectomy
• Functional assessment of splenules may be more important than their size 3
• Splenules may be the cause of disease relapse in post-splenectomy patients with autoimmune hematologic disorders

Pitfalls:

• Splenules can be mistaken for neoplasms, particularly when located near the pancreatic tail 6
• Failure to identify accessory splenic tissue during splenectomy can lead to treatment failure in conditions like ITP
• Overlooking the possibility of symptomatic splenules in patients with prior splenectomy and recurrent symptoms

In conclusion, while most splenules are asymptomatic, they can cause significant pain and clinical symptoms when affected by pathological processes such as torsion, infarction, or trauma.