Mucinous cystic neoplasm of the pancreas is not an aggressive entity: lessons from 163 resected patients

Abstract

Objective: Mucinous cystic neoplasms (MCNs) of the pancreas have often been confused with intraductal papillary mucinous neoplasms. We evaluated the clinicopathologic characteristics, prevalence of cancer, and prognosis of a large series of well-characterized MCNs in 2 tertiary centers.

Methods: Analysis of 163 patients with resected MCNs, defined by the presence of ovarian stroma and lack of communication with the main pancreatic duct.

Results: MCNs were seen mostly in women (95%) and in the distal pancreas (97%); 25% were incidentally discovered. Symptomatic patients typically had mild abdominal pain, but 9% presented with acute pancreatitis. One hundred eighteen patients (72%) had adenoma, 17 (10.5%) borderline tumors, 9 (5.5%) in situ carcinoma, and 19 (12%) invasive carcinoma. Patients with invasive carcinoma were significantly older than those with noninvasive neoplasms (55 vs. 44 years, P = 0.01). Findings associated with malignancy were presence of nodules (P = 0.0001) and diameter > or =60 mm (P = 0.0001). All neoplasms with cancer were either > or =40 mm in size or had nodules. There was no operative mortality and postoperative morbidity was 49%. Median follow-up was 57 months (range, 4-233); only patients with invasive carcinoma had recurrence. The 5-year disease-specific survival for noninvasive MCNs was 100%, and for those with invasive cancer, 57%.

Conclusions: This series, the largest with MCNs defined by ovarian stroma, shows a prevalence of cancer of only 17.5%. Patients with invasive carcinoma are older, suggesting progression from adenoma to carcinoma. Although resection should be considered for all cases, in low-risk MCNs (< or =4 cm/no nodules), nonradical resections are appropriate.

Figures

FIGURE 1

Scatter plot of radiologic tumor size as a function of histologic subtype, and presence of nodules.

FIGURE 2

Overall 5- and 10-year actuarial survival for the entire series (n = 163) was 93% and 84%, respectively.

FIGURE 3

The 5-year disease-specific survival was 100% for patients affected by adenoma, borderline neoplasm, or carcinoma in situ (black line), and 57% for those with invasive carcinoma (hatched line).