Natural history of branch duct intraductal papillary mucinous neoplasm with mural nodules: a Japan Pancreas Society multicenter study.
OBJECTIVE
This study aimed to elucidate the natural history of intraductal papillary mucinous neoplasm (IPMN) of the pancreas with mural nodules (MNs) in branch duct IPMN (BD-IPMN).


METHODS
Among the 402 registered patients with BD-IPMN on long-term follow-up at 10 institutions in Japan, 53 patients with MNs of less than 10 mm in height detected by endosonography were included in this study. The morphological changes of the BD-IPMN in these patients and histologic findings of the resected specimen were investigated.


RESULTS
The median height of the MNs at the initial diagnosis was 3 mm (range, 1-8 mm), and 12 (23%) of the 53 patients showed an increase in the height of the MNs during follow-up (mean duration, 42 months). Six patients underwent surgery because of an increase in the height of MNs, yielding high-grade dysplasia in 1 patient and low-grade dysplasia in 5 patients. No patients developed invasive carcinoma derived from IPMN, and distinct pancreatic ductal adenocarcinoma developed in 1 (2%) patient. The incidence of the development of malignancy in BD-IPMNs, including distinct pancreatic ductal adenocarcinoma, was similar to that of those without MNs.


CONCLUSIONS
In patients who have BD-IPMN with MNs of less than 10 mm in height, observation instead of immediate resection is considered to be possible.
From the *Department of Gastroenterology, Sendai City Medical Center, Sendai; †Center for Gastroenterology, Teine-Keijinkai Hospital, Sapporo; ‡Department of General Medicine, Asahikawa Medical College, Asahikawa; §Department of Gastroenterology, Aichi Cancer Center Hospital, Nagoya; ∥Center for Gastroendoscopy, Onomichi General Hospital, Hiroshima; ¶Department of Surgery, Institute of Gastroenterology, Tokyo Women's Medical University, Tokyo; #Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka; **Department of Gastroenterology, Chiba Cancer Center, Chiba; ††Department of Gastroenterological Surgery, Tokai University School of Medicine, Kanagawa; ‡‡Department of Hepato-Biliary-Pancreatic Surgery and Transplantation, Kyoto University; and §§Department of Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Go
G
Kobayashi
Naotaka
N
Fujita
Hiroyuki
H
Maguchi
Satoshi
S
Tanno
Nobumasa
N
Mizuno
Keiji
K
Hanada
Takashi
T
Hatori
Yoshihiko
Y
Sadakari
Taketo
T
Yamaguchi
Kousuke
K
Tobita
Ryuichiro
R
Doi
Akio
A
Yanagisawa
Masao
M
Tanaka
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D021441:Carcinoma, Pancreatic Ductal / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D018450:Disease Progression; D019160:Endosonography; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D018297:Neoplasms, Cystic, Mucinous, and Serous / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D011237:Predictive Value of Tests; D012042:Registries; D012189:Retrospective Studies; D012955:Societies, Medical; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden; D057832:Watchful Waiting