Watchful waiting for large primary nonparasitic splenic cysts.

Background: Primary nonparasitic splenic cysts (NPSC) are typically diagnosed incidentally. The management of large (≥ 5 cm) asymptomatic cysts remains controversial; there is a lack of evidence guiding management. The purpose of this study was to describe the outcomes of nonoperative management of large NPSC.

Methods: Patients diagnosed with NPSC between January 2004 and December 2019 were identified at our academic institution. Adult patients with an NPSC of at least 5 cm who had at least 1 additional hospital visit were included. Data are presented as medians with interquartile ranges (IQR).

Results: We identified 512 medical records that included the term splenic cyst during the study period. Sixty-eight of the patients had no reported cyst size, 410 had cysts smaller than 5 cm, 1 patient underwent an elective splenectomy at another institution and 12 patients were excluded for other reasons; 21 patients with cysts of at least 5 cm were included in the study. Eight symptomatic patients underwent surgery at our institution. Of these, 2 presented acutely: 1 with hemoperitoneum who required admission for transfusions and later underwent elective laparoscopic splenectomy and 1 with increasingly severe abdominal pain who underwent laparoscopic cyst unroofing. The remaining 6 symptomatic patients had elective surgery for pain (4 cyst unroofing, 1 total splenectomy, 1 partial splenectomy). Thirteen patients were asymptomatic (10 female, median age 49.2 [IQR 38.1 to 64.6] yr). Two of these patients chose to undergo elective surgery. The remaining 11 asymptomatic patients, with a median initial cyst size of 8.0 (IQR 5.3 to 10.8) cm, were followed for a median of 31.0 (IQR 23.5 to 71.0) months. There was no change in median cyst size (0 [IQR -1 to 0] cm), and none of these patients underwent intervention for their NPSC.

Conclusion: Asymptomatic patients managed nonoperatively for large NPSC did not become symptomatic or require intervention during the study period. This supports watchful waiting with serial radiologic and clinical monitoring for asymptomatic large NPSC.