Splenic disorders

Key points

Embryology

• Week 4: Mesenchymal condensation occurs within the dorsal mesogastrium

• Weeks 6-7: Gastric rotation shifts the developing spleen from the midline to the left abdominal cavity. During this period, cell clusters coalesce and vascularise

Splenogonadal Fusion

• Typically presents as a testicular mass, but can also be located in the abdomen or attached to the testis

• Forms:

  • Continuous: Includes a band of fibrous connective tissue and is often associated with other congenital anomalies

  • Discontinuous: Lacks connection to the native spleen, usually isolated and often considered an ectopic or accessory spleen

• Management: Resection of ectopic tissue, potential salvage or removal of the left testis, and repair of any hernia defects

Splenopancreatic Fusion

• Complications: Surgical challenges due to anatomical anomalies in the spleen and pancreas area

Wandering Spleen

• Absent splenic attachments

• Requires splenopexy. Preoperative vaccination is necessary due to potential functional asplenia from chronic torsion

Accessory Spleens (Splenunculi)

• Found in 20-30% of the population

• Commonly near the splenic hilum, within splenic ligaments, omentum, or tail of the pancreas

• Usually solitary but can number two or three

• Provides some immune function and red blood cell processing. Beneficial post-traumatic splenectomy, but may require removal in certain haematological conditions necessitating therapeutic splenectomy

Splenic Cysts

• Types:

  • Congenital: Arise from mesothelial inclusions

  • Acquired: Result from haematoma or infection

• Infectious Causes:

  • Bacterial: Sepsis or endocarditis

  • Fungal: Typically in immunocompromised individuals

  • Hydatid Cysts: Caused by Echinococcus species, prevalent in the Mediterranean, Middle East, North Africa, Australia, and New Zealand

    
    

    Imaging: Shows small daughter cysts at the spleen periphery; concurrent liver disease may be present

    
    

    Treatment: Cysts >5cm require intervention, usually aspiration and sclerotherapy. Laparoscopic marsupialisation if unsuccessful. Hydatid cysts may need an open procedure with hypertonic saline instillation and potentially a splenectomy. Postoperative Mebendazole is required to prevent recurrence

Splenic Masses

• Types:

  • Haemangiomas and Hamartomas: Usually incidental findings

  • Splenosis: Seeding of the peritoneum post-splenic rupture; benign but with limited immune function

Overwhelming Post-Splenectomy Infection (OPSI)

• Highest risk in children under 5 years old, with mortality rates up to 50%

• Frequently occurs within weeks post-splenectomy in non-vaccinated patients; in vaccinated individuals, it occurs 2-3 years postoperatively

References

Kapila V, Wehrle CJ, Tuma F. Physiology, Spleen. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537307/

Skarsgard, Erik D, and Mary L Brandt. "Splenic Anatomic Disorders." Pediatric Surgery NaT, American Pediatric Surgical Association, 2020. Pediatric Surgery Library, www.pedsurglibrary.com/apsa/view/Pediatric-Surgery-NaT/829058/all/Splenic_Anatomic_Disorders.

Skarsgard, Erik D, and Mary L Brandt. "Splenic Disorders." Pediatric Surgery NaT, American Pediatric Surgical Association, 2020. Pediatric Surgery Library, www.pedsurglibrary.com/apsa/view/Pediatric-Surgery-NaT/829054/all/Splenic_Disorders.