Observation of mucinous cystic neoplasms (MCN):

A study of 46 patients with MCN and MCN-like lesions

Abstract

Background: Suspected pancreatic mucinous cystic neoplasms (MCN) are often resected in Japan, but patients without malignant findings have undergone observation only in Europe and the United States. Therefore, we examined the propriety and methods of follow-up of patients with suspected MCNs.

Methods: We examined factors predictive of malignancy in 46 patients treated at our hospital with suspected MCN or a confirmed diagnosis of MCN.

Results: The positive predictive value of preoperative diagnosis of MCN was 71% and the sensitivity was 89%. Outcomes were classified according to 29 patients with MCN (malignant 9 / benign 20), 10 with similar diseases (malignant 3 / benign 7), and 7 suspected MCN lesions (not resected). There were no deaths among patients with MCN adenomas and noninvasive carcinomas. All MCNs with mural nodules <5mm and cyst diameter <40mm were adenomas. In patients with similar diseases, it was possible to distinguish between benign and malignant by this criterion. In addition, it was suggested that an increase in size of >10mm/year and calcification might be a predictive factor for malignancy.

Conclusion: Based on the criteria of "a mural nodule <5mm and cyst diameter <40mm", it is considered possible to follow-up lesions suspected to be MCN.