Pancreatic mucinous cystic neoplasms (MCN) during pregnancy grow rapidly and undergo malignant transformation: A series of 69 operated cases

Background The diagnosis of mucinous cystic neoplasm (MCN) during pregnancy is rare and presents unique challenges. We analyzed all reported cases of pregnancy-associated MCNs to assess malignant potential and identify predictive factors. Methods A total of 69 patients with MCN were included: 65 from systematic literature search and 4 cases from our institutional databases. Data included patient demographics, symptoms, diagnostics, surgical management, histopathology, and clinical outcomes. Results The median age was 33 years (range 20–47). 74% (49/66) presented with symptoms. Tumor-related complications occurred in 27% (16/60), including acute pancreatitis in eight and cyst rupture in four. Median MCN diameter at diagnosis was 12.0 cm (1.5–30). Median tumor growth during pregnancy was 2.5 cm (0.5–20) over a median period of 2.75 months (1–78). All patients underwent surgical resection: 29% (20/69) in second trimester and 59% (41/69) postpartum. Postoperative complications occurred in four patients, all including pancreatic fistula or fluid collection. Fetal complications were reported in eight cases, without tumor-related mortality. 20% (13/66) had invasive adenocarcinoma (IC), 14% (9/66) high-grade dysplasia (HGD), and rates were similar if resected during pregnancy or postpartum. Symptomatic presentation and high-risk imaging features significantly correlated with malignant MCN. During the median follow-up of 24 months (2–154), local recurrence occurred in three patients and one patient died. Conclusions Pregnancy-related MCNs were typically large, symptomatic, and grew rapidly. A third of tumors harbored IC or HGD. Prompt surgical resection, typically during the second trimester appears safe, with a low rate of maternal and fetal complications.