Introduction
Tumors of the duodenal minor papilla are very rare. In contrast to tumors of the major
papilla, those of the minor papilla are less symptomatic unless they grow large or
are accompanied by pancreatic duct anomalies [1]. Consequently, such tumors are incidental findings made during health screenings.
As with other duodenal lesions, most tumors of the minor papilla are treated by laparotomy,
including pancreatoduodenectomy, papillectomy, and duodenectomy [1]
[2]
[3]. In cases of adenoma or dysplasia located at the major papilla, endoscopic papillectomy
(EP) is the least invasive and curative procedure when the neoplasm is limited to
the duodenum and common channel [4]
[5]. However, to date, only a few cases of endoscopic resection have been reported for
noninvasive tumors of the minor papilla, which differ in anatomic characteristics
from those of the major papilla.
Case report
A 69-year-old woman was referred to our hospital for investigation and treatment of
a duodenal tumor. Laboratory data, including tumor markers and pancreatic enzymes,
were all within normal ranges. On referral, endoscopic examination demonstrated a
slightly elevated, multilobular tumor at the minor papilla of the duodenum, approximately
12 mm in size. Under sprinkling indigo carmine pigment, no ulceration, depressed areas,
or large nodules suggestive of an invasive component were evident macroscopically
([Fig. 1 a, b]). The major ampulla of Vater was normal ([Fig. 1 c]). Endoscopic retrograde cholangiopancreatography (ERCP) revealed no obvious tumor
extension to the Santorini duct ([Fig. 2]). No anomaly of the pancreatobiliary ductal system was recognized and the contrast
medium was fully excreted from the major papilla after withdrawal of the catheter.
A biopsy from the minor papilla demonstrated histology of adenoma with severe atypia
(or high-grade dysplasia). Based on these findings, we diagnosed a tumor limited to
the mucosal layer of the minor papilla with a good indication for endoscopic mucosal
resection (EMR).
Fig. 1 Side-viewing endoscope view of a tumor of the minor duodenal papilla. a Oral-side view. b Anal-side view. c Intact orifice of the major papilla. d A glycerol-injected and well-lifted tumor. e Electric snare ligation. f An ulceration after endoscopic mucosal resection (EMR) without remnant tumor.
Fig. 2 Endoscopic retrograde pancreatography by cannulation from the major papilla demonstrating
intact Wirsung and Santorini ducts without pancreatobiliary duct malformations.
EMR was performed the day after admission. Glycerol was first injected into the submucosa
to separate the muscularis propria, facilitate easier resection, and prevent perforation
([Fig. 1 d]). A well-elevated lesion was ligated and cut using an electric snare (Captivator,
Boston Scientific, Alajuela, Costa Rica) with an endocut mode of electrification (cutting
at maximum: 120 watt, ERBE ICC 200, Marietta, U.S.A) ([Fig. 1 e]). A resected sample was collected using a net (Roth Net®, US endoscopy, Ohio, U.S.A). Finally, the ulceration after the EMR was confirmed
to be negative for any remnant lesion, bleeding, or perforation ([Fig. 1 f]). The endoscopic procedure was completed without stent placement to the minor papilla.
No pancreatitis or other complications occurred related to the endoscopic procedure.
The patient began eating on the second day after EMR and she was discharged as scheduled.
Histology of the EMR material showed an adenocarcinoma (carcinoma in situ) component
within the adenoma (11 × 8 mm) and all cut ends were negative for any neoplastic extension
([Fig. 3]). For post-EMR surveillance, upper gastrointestinal endoscopy was continued, first
at 6-months intervals and then annually. Eighty months have passed since the EMR and
the patient remains healthy with no evidence of recurrence, increasing level of serum
amylase, or dilation of the pancreatic duct.
Fig. 3 Histology of the EMR sample of the minor papilla. a A low-power view of the EMR specimen showing a flat-elevated epithelial lesion of
the minor papilla. b A magnified view of the orifice epithelia histologically showing adenocarcinoma in
situ accompanied by a high-grade adenoma component. c A high power view of the Santorini duct without extension of the neoplastic cells.
Discussion
A variety of tumors have been reported at the minor papilla of the duodenum, including
endocrine tumors, adenomyomas, and adenocarcinomas. Most of these cases have been
treated by laparotomy [1]
[2]
[3]. Early-stage tumors of the major papilla (although the indication is still arguable
[4]
[5]) are increasingly treated by endoscopic resection with relative ease and low invasiveness.
However, to date, only a few cases of endoscopic resection have been reported for
the tumors of the minor papilla [6]
[7]. Therefore, no consensus exists regarding the indication and method of endoscopic
treatment.
Ampullary adenoma without ductal extension into the bile/pancreatic duct is currently
considered an indication for EP for tumors of the major papilla [4]
[5]
[8]. Containment of the adenoma and limitation within the ampullary duodenum and common
duct suggest the so-called intestinal-type, a noninvasive tumor of the papilla of
Vater [9]. However, application of this indication to the minor papilla requires that we bear
in mind the differences in anatomic characteristics of the two duodenal papillae.
First, the minor papilla is usually not a main exit for pancreatic juice secretion,
suggesting a lower risk of post-resection pancreatitis if the pancreatic duct’s anomaly
does not exist and the major papilla is intact. In this sense, Trevino et al. reported
an interesting case of minor papilla adenoma accompanied with pancreatic divisum and
successfully treated by endoscopic resection with placement of a plastic stent to
the dorsal pancreatic duct [7]. In another case in their series, tubulovillous adenoma was confirmed at both major
and minor papilla, and they successfully resected both of these lesions at one session
with a stent insertion to the Wirsung duct as prophylaxis for post-procedure pancreatitis
[7]. Second, the surrounding muscular construction is not as massive for the minor papilla
as it is for the major papilla [10]. Hence, unlike the case for the major Vater, a lesion can be lifted significantly
by submucosal injection, which probably enabled an easier en-bloc resection in the
current case, even of a flat elevated lesion, with less risk of bleeding or perforation.
One concern is that the minor papilla often contains pancreatic tissue (80 %) [10] and the area lined by the pancreas may not be as wide as that of the major Vater.
Therefore, risks of perforation may increase in cases of laterally spreading tumors
resected without submucosal injection.
With epithelial neoplasms of the major and minor papillae, evaluation of the intraductal
extension of the neoplastic cells often is problematic and it is sometimes difficult
even when using endoscopic ultrasonography (EUS) or intraductal ultrasonography (IDUS)
[4]
[5]. The operator can judge ductal extension as positive if it is recognized as a millimeter
level of neoplastic component in the bile/pancreatic duct by either EUS or IDUS. However,
a single layer of neoplastic cell extension is < 20 μm thick and cannot be distinguished
with clinical imaging. In our case, we denied the macroscopic level of Santorini duct
extension by ERP ([Fig. 2]) and planned to add laparotomy if the carcinoma was positive, even at the microscopic
level, at the cut end of the pancreatic duct ([Fig. 3 c]).
EMR is considered a good treatment option for noninvasive tumors of the duodenal minor
papilla that show no intraductal extension to the dorsal pancreatic duct. Experience
with more of these types of cases is needed to reach consensus regarding the optimal
method for diagnosing and treating tumors of the duodenal minor papilla.
