Partial decapsulation of splenic epithelial cysts: studies on etiology and outcome

Purpose : The presence of squamous epithelium in the cyst wall of children with large splenic cysts has generally been thought to require complete resection of the cyst lining to prevent recurrence. The risks of major bleeding or possible total splenectomy necessitates a simplified procedure to preserve splenic function without cyst recurrence. Methods : Six patients treated for splenic cyst over a 10-year period underwent partial splenic decapsulation retaining the hilar portion of the spleen. The patient group, including five girls, ranged in age from 6 to 18 years (mean, 13 years). Presenting findings were splenomegaly (n = 4), progressive cyst enlargement (n = 4), left upper quadrant pain (n = 2), ultrasound for unrelated condition (n = 2), and prior history of trauma (n = 1). Cyst location varied from peripheral to deep cortical and ranged in size from 5 to 20 cm containing from 200 to 1,700 mL of sterile straw-colored to dark brown-colored liquid. Results : Palpable splenomegaly resolved in all patients with progressive decrease in size of the splenic remnant, and return of vascularity to normal was confirmed by Doppler ultrasound. Each patient remains asymptomatic without recurrence of the splenic cyst from 1 to 10 years after surgery. Squamous epithelial lining cells found in sheets and clusters were seen within the cyst lining of all patients. Immunohistochemistry of the paraffin-embedded tissue showed that these cells expressed keratin, epithelial membrane antigen (EMA), carcino-embryonic antigen (CEA), but were negative for BerEP4 (conventionally positive in cells of epithelial origin). Conclusion : The authors conclude that splenic decapsulation is an effective treatment for splenic epithelial cysts, which both preserves splenic function and prevents recurrence despite retention of hilar cyst lining. Epithelial metaplasia of the mesothelial-mesodermal undifferentiated cells from exposure to an unidentified irritant may explain the histological presence of squamous epithelium within the cyst wall.