- Email: [email protected]
Surgical indications for small polypoid lesions of the gallbladder
Surgical Hiroshi
Indications for Small Polypoid Lesions of the Gallbladder
Shinkai,
MD, Wataru
Kimura, MD, Tetsuichiro
BACKGROUND: To determine which polyps of the gallbladder should be operated upon, we investigated the size and number of polyps in resected gallbladders, and studied changes in gallbladder polyps using ultrasonography (US). METHODS: We studied 74 resected gallbladders with small polypoid lesions less than 20 mm in diameter, and 60 patients with gallbladder polyps by US. The polyps in resected gallbladders were classified into four groups histologically, and clinical features, maximum diameter, and number of lesions were compared among the groups. In the followed-up cases with gallbladder polyps, the size and number of polyps were examined by US, and changes during the observation period were studied. RESULTS: The mean diameter of adenoma was 6.00 k 3.39 mm (mean rl: SD) and that of cancer 10.6 -c 4.16 mm; 97% of cholesterol polyps were less than 10 mm in diameter (3.66 f 2.66 mm). Neoplastic polyps tended to be single (adenoma, n = 1.40 f 0.89; cancer, n = 1.16 +- 0.40), whereas half of the cholesterol polyps were multiple (n = 3.09 -+ 3.31). However, when there were fewer than 3 lesions, the incidence of neoplasm was 37% among polyps 5 to 10 mm in diameter. A low incidence (6%) of neoplasm was also observed among polyps less than 5 mm in diameter. CONCLUSIONS: These data indicate that an aggressive surgical approach for small gallbladder polyps is warranted when there are fewer than 3 polyps, regardless of their size. Am J Surg. 1998;175:114-117. 0 1998 by Excerpta Medica, Inc.
I
t is well known that most benign polypoid lesions in the gallbladder are cholesterol polyps.’ Ultrasonography (US) is considered to be useful for differentiating malignant from benign lesions, since the specificity of US in the diagnosis of gallbladder polyps is 93.9%.* In addition, by using endoscopic US (EUS), even large cholesterol polyps larger than 10 mm in diameter can be diagnosed correctly based on the characteristic aggregation of echo-
Muto, MD,
Tokyo, Japan
genie spots in the p01yps.~ On the other hand, the early diagnosis of gallbladder cancer before surgery is difficult4-6 and long-term survival is most often expected in cases in which an unsuspected carcinoma is resected for treatment of cholecystolithiasis.7 Therefore, we should try to more precisely differentiate benign polypoid lesions of the gallbladder from malignant lesions. In the present study, we investigated the size and number of polypoid lesions in resected gallbladders, and studied the changes in gallbladder polyps in cases followed by US to determine which gallbladder polyps should be surgically resected.
MATERIAL
AND METHODS
Resected Gallbladders with Polypoid Lesions less than 20 mm in Diameter From January 1980 to December 1995, 667 cholecystectomies were performed for hepatobiliary or other diseases at the First Department of Surgery, Faculty of Medicine, University of Tokyo. Of these 667 resected gallbladders, 74 (11%) had small polypoid lesions less than 20 mm in diameter. The polypoid lesions were classified into four groups histologically: cholesterol polyp, adenoma, cancer, and other. “Other” lesions consisted of hyperplastic polyp, granulation, and adenomyomatosis in the form of a polypoid lesion. Clinical features such as age, gender, cholecystolithiasis, and the maximum diameter and number of lesions were compared among the four groups. Cases with more than 10 lesions were considered to have 10 lesions for analysis purposes. Gallbladder Polyps Followed-up Using Ultrasonography From January 1990 to October 1995, 60 patients with gallbladder polyps were followed up by US. Thirty-five patients were males and 25 were females. The polyps were diagnosed ultrasonographically as cholesterol polyps or benign polyps, and did not include lesions that suggested neoplasms because they should have been excised immediately. The maximum diameter and the number of polyps were examined by US, and changes during the observation period were studied. All results are presented as the mean t SD. Statistical significance was determined at P co.05 by the Wilcoxon test.
RESULTS From the First Department of Surgery, University of Tokyo, Tokyo, Japan. Requests for reprints should be addressed to Hiroshi Shinkai, LID, First Department of Surgery, University of Tokyo, 7-3-l iongo, Bunkyo-ku, , Tokyo 113, Japan. Manuscript submitted October 25, 1996 and accepted in rerised form April 29, 1997.
114
0 1998 by Excerpta All rights reserved.
Medica,
Inc.
Resected Gallbladders with Small Polypoid Lesions The clinical features of the 74 patients are shown in Table I. Cholesterol polyps were found in 44 (59%) cases, adenomas in 5 (7%) cases, cancers in 6 (8%) cases, and other conditions in 19 (26%) cases. Although the mean age of patients with adenoma (44.8 t 15.5 years) tended to be less than those in the other groups, these differences 0002-961 O/98/$1 PII SOOO2-9610(97)00262-6
9.00
1 SURGICAL
I
TABLE
INDICATIONS
FOR
GALLBLADDER
POLYPOID
LESIONS/SHINKAI
ET AL
I Clinical
Type of Lesion Cholesterol POlYP n = 44 (59%) Adenoma n = 5 (7%) Cancer n = 6 (8%) Other n = 19 (26%)
Features
Age (Y) (Mean f SD)
of Cases Gender (MS)
of Small
Polypoid
2 13.4
1:0.91
12 (27%)
44.8
2 15.5
1 :1.5
1 (20%)
in 74 Resected
Gallbladders Number
Maximum Diameter (mm, Mean + SD)
Gallstones
54.3
Lesions
Mean
-c SD
3.66
? 2.68
3.09 + 3.31
6.00
z 3.39 ‘I t
1.40 + 0.89
I
of Lesions Solitary
Multiple
50%
50%
80%
20%
83%
17%
76%
24%
W)
VW
* 59.8 57.0
2 13.9 2 11.8 WY
The maximum diameter of cholesteroipolyp hand, other lessons and neoplastic polyps
1:2.0 1:0.90
3 (50%)
10.83
11 (58%)
5.65
*
k 4.16
1
l
1.16 + 0.40
*
t
t 4.06
1.31 t 0.67
U’JS)
was iess than 5 mm (3.66 2 2.68 mm). and ha/f of them were mu/t!pie with a mean of 3.09 2 3.3 I /es/ox tended to be single, and the number of lesions in cancer cases was almost 1.OO (1.16 t 0.40).
On the other
* P 10.05. t P <0.0001. NS = not significant.
were not significant. Male:female ratios were about 1:0.9 for nonneoplasms (cholesterol polyp and other), whereas there were more females than males among patients with neoplasms (adenoma and cancer). Again, this difference was not significant. The incidence of cholecystolithiasis was highest (58%) in the other group and lowest (27%) in the cholesterol polyp group (P ~0.05). In neoplastic polyps, gallstones were present in 50% of cancer and in 20% of adenomas (not significant). The maximum diameter of cholesterol polyp was less than 5 mm (3.66 ? 2.68 mm). Other lesions (5.65 * 4.06 mm) and adenoma lesions (6.00 ? 3.39 mm) were larger than cholesterol polyp, and the mean diameter of cancer lesions was more than 10 mm (10.8 t 4.16 mm). Almost all (97%) cholesterol polyps were less than 10 mm in diameter, and 82% were smaller than 5 mm. The number of lesions in each group also differed. Half of the cholesterol polyps (50%) were multiple with a mean of 3.09 ? 3.31 lesions. On the other hand, other lesions and neoplastic polyps tended to be single, with means of 1.31 -’ 0.67 and 1.40 2 0.89, respectively. The number of lesions in cancer cases was almost 1.00 (1.16 t 0.40). In adenoma, only 1 case (20%) had multiple polypoid lesions in the gallbladder, which consisted of one adenoma (7 mm) and two cholesterol p01ps (each 2 mm). One case in the cancer group (17%) showed two lesions (10 mm, 4 mm), both of which were polypoid carcinomas histologically. The relationship between the size and the number of polypoid lesions in the present study is shown in the Figure. In summary, cholesterol polyps were usually less than 10 mm in diameter, and polypoid lesions larger than 10 mm in diameter were frequently neoplasms. All of the cases with 4 or more polyps in the gallbladder were cholesterol polyps. When the number of lesions was less than 3, the incidence of neoplasm was 37% among polyps 5 to 10 mm in diameter. A low incidence (6%) of neoplasm was also observed with polyps less than 5 mm in diameter. THE AMERICAN
lb maximum
Figure. cording lesions
diameter
of polypoid
The incidence of neoplasms to the maximum diameter in resected gallbladders.
1'5 lessons
and cholesterol and the number
polyps acof polypoid
Gallbladder Polyps Followed up by US The 60 patients consisted of 35 males and 25 females who ranged in age from 28 to 74 years. There was no difference in mean age between males (50.5 + 11.4 years) and females (53.1 2 12.4 years). Cholecystolithiasis was detected in 5 cases (S%), wall thickness in 4 (7%), and cholesterolosis in 4 (7%) by US. Overall changes in the maximum diameter and number of lesions are shown in Table II. At the first examination, the mean diameter was 4.80 * 2.9 mm and the average number of lesions was 2.06 ? 2.2. After a mean observation period of 22.2 month ( 1 month to 9 years), neither the size nor the number of lesions changed significantly. The maximum increase in diameter was +4 mm (2 cases) over 5 months and 30 months, respectively. Overall, laparoscopic cholecystectomies were performed in 9 patients after a mean observation period of 13.1 months. The presence of symptoms or an increase in size was one of the reasons for operation in these 9 patients. However, most of them had hoped to be operated on, with informed consent, concerned about the gallbladder polyps. Seven of these cases were histologically diagnosed as cholesterol polyps, 1 as iadenoma (3 mm, solitary), and 1 as dysplasia (2 mm, solitary). JOURNAL
OF SURGERYe’
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FEBRUARY
1998
115
IJRGICAL
INDICATIONS
FOR
GALLBLADDER
POLYPOID
LESIONWSHINKAI
TABLE II Changes in Maximum Diameter and Number of Lesions in 60 Cases with Gallbladder Polyps Followed up by Ultrasonography Maximum Diameter of Polyps (mm) (Mean f SD) At first examination At final examination
4.80 4.33
1 2.9 1 3.2 VW
After a mean obsewatlon the size nor the number NS = not significant.
Number of Polyps (Mean f SD) 2.06 2.26
+ 2.2 + 2.9 VW
period of 22.2 months (1 month of lesions changed significantly.
to 9 years),
nerther
COMMENTS Gallbladder polyps are common in the general population. The prevalence was 4.6% among men and 4.3% among women in a random population in Denmark.” However, among healthy Japanese, that was found to be 6.28% among men, significantly higher than the 3.51% in women, and the racial differences deserved further consideration.” There are several comparisons of the size and number of polyps in benign and malignant lesions. 1,2.1o-1i Most authors believe that malignancy should be suspected or that surgical treatment should be indicated when the polyp is more than 10 mm in diameter and/or when the polypoid lesion is solitary. In the present study, 82% of cholesterol polyps were less than 5 mm in diameter, and 97% were less than 10 mm in maximal diameter. We have not experienced cholesterol polyps or inflammatory polyps over 15 mm in diameter, whereas we have encountered many polypoid lesions more than 20 mm in diameter among neoplasms. Therefore, we always consider gallbladder polyps over 15 mm in diameter to be neoplasms. Although half of the cholesterol polyps in this study were multiple and neoplasms tended to be single, there were also many solitary chopolyps including lesterol polyps (50%) and multiple nroplasms. These results suggest that even if polypoid lesions are less than 5 mm in diameter, or even if the lesions are multiple, neoplastic polyps may be present if there are fewer than 3 polyps. In the cases with gallbladder polyps that we followed up by US, the overall average size and number of lesions did not change. Ukai et al’” reported a case of cholesterol polyp that showed a 40% increase in diameter over 10 months. However, similar cases are infrequent, and most cholesterol polyps do not change in either size or number. Compared with the resected cholesterol polyps, the followed-up polyps were larger in diameter and fewer in number. This can be explained in part by the fact that small polyps that can be found in resected specimens are sometimes not detected by US. None of the 9 patients who underwent surgery after follow-up by US had polypoid cancer, but 1 case of adenoma was found. Although adenoma is not a malignant neoplasm, the premalignant potential of gallbladder adenoma and the adenoma-carcinoma sequence are unquestionable.5,‘7-1’ In addition, adenomyomatosis of the gallbladder has recently been suggksted to have malignant poten116
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ET AL
gallbladder polyps should be opertial. 5.20-22 Naturally, ated upon when the lesion is suspected to be neoplasm, such as a sessile lesion.“,‘5 In addition, adenomas or inflammatory polyps may also be considered as candidates for resection as premalignant polyps. On the other hand, cholecystolithiasis was frequently found among polyps classified as other or cancer lesions in the present study. Many cases of other lesions were inflammatory, and it is likely that gallstones caused the inflammation. The high incidence of cholecystolithiasis in cancer lesions may suggest a relationship between cancer and gallstones, as previously reported.” Although the present study population was too small to evaluate this relationship, these results indicate that gallbladder polyps with cholecystlithiasis should be removed. In the present cases with cholesterol polyps that we observed, the size and number of lesions did not change. Therefore, follow-up by US is still significant as a means of distinguishing those patients who should be operated upon from those who merit continued observation. However, early cholecystectomy is recommended for gallbladder polyps in order to Identify the early or unsuspected gallbladder cancer. In conclusion, an aggressive surgical approach for small gallbladder polyps is warranted when there are fewer than 3 polyps, regardless of their size.
REFERENCES 1. Koga A, Watanabe K, Fukuyama T, et al. Diagnosis and operative indications for polypoid lesions of the gallbladder. Arch Surg. 1988;123:26-29. 2. Yang HL, Sun YG, Wang 2. Polypoid lesions of the gallbladder: diagnosis and indications for surgery. Br J Surg. 1992;79:227-229. 3. Sugiyama M, Atomi Y, Kuroda A, et al. Large cholesterol polyps of the gallbladder: diagnosis by means of US and endoscopic US. Rudioloa. 1995;196:493-497. 4. Kimura W, Nagai H, Kuroda A, et al. Clinicopathologic study of asymptomanc gallbladder carcinoma found at autopsy. Cancer. 1989;64:98-103. 5. Aldridge MC, Gruffz F, Castaing D, et al. Adenomyomatosis of the gallbladder. A premalignant lesion? Surgery. 1991;109:107-110. 6. Vallilengua C, Rodriguez OJ, Proske SA, et al. Imprint cytology of the gallbladder mucosa. Its use in diagnosing macroscopically inapparent carcinoma. Acra Cytol. 1995;39:19-22. 7. Nadler LH, McSherry CK. Carcinoma of the gallbladder: review of the literature and report on 56 cases at the Beth Israel Medical Center. LMtSinai J Med. 1992;59:47-52. 8. Jorgensen T, Jensen KH. Polyps in the gallbladder. A prevalence study. Stand J Gastroenterol. 1990;25:281-286. 9. Segawa K, Arisawa T, Niwa Y, et al. Prevalence of gallbladder polyps among apparently healthy Japanese: ultrasonographic study. Am J Gasaoenterol. 1992;87:630-633. 10. The First Department of Medicine, Chiba University School of Medicine, Chiba, et al. Collective review of 503 cases of small polypoid lesions (less than 20 mm in maximum diameter) of the gallbladder: size distribution in various diseases and the depth of carcinomatous invasion. Uapanese]. Nippon Shokakibyo Gakkai Zasshi. 1986;83:2086-2087. 11. Iahlkawa 0, Ohhiqashi H, Imaoka S, et al. The difference in malignancy between pedunculated and sessile polypold lesions of the gallbladder. Am J Gastroenterol. 1989;84: 1386-1390. 12. Farinon AM, Pacella A, Cetta F, et al. “Adenomatous polyps of the gallbladder” adenomas of the gallbladder. Hpb Surg. 1991;3: 251-8. FEBRUARY
1998
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INDICATIONS
13. Edelman DS. Carcinoma of a gallbladder polyp: treated by laparoscopic laser cholecystectomy. Surg Laparosc Endosc. 1993;3: 142-143. 14. Chijiiwa K, Tanaka M. Polypoid lesion of the gallbladder: indications of carcinoma and outcome after surgery for malignant polypoid lesion. Int Surg. 1994;79:106-109. 15. Kubota K, Bandai Y, Nole T, et al. How should polypoid lesions of the gallbladder be treated in the era of laparoscopic cholecystectomy? Surgery. 1995;117:481-487. 16. Ukai K, Aklta Y, Mizuno S, et al. Cholesterol polyp of the gallbladder showing rapid growth and atypical changes-a case report. Hepatogastroenterolo~. 1992;39:371-373. 17. Sato H, Tahara M, Kono M, et al. Minute gallbladder cancercase report with suggestions regarding a possibly unique histogenesis. uapanese]. Grin No Rinsho. 1984;30:843-848. 18. Nakajo S, Yamamoto M, Tahara E. Morphometrical analysis of gall-bladder adenoma and adenocarcinoma with reference to his-
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ET AL 1
togenesis and adenoma-carcinoma sequence. Virchows Arch ‘4 Pathol Anat Histopnthol. 1990;417:49-56. 19. Kimura W, Muto T, Esaki Y. Incidence and pathogenesis of villous tumors of the gallbladd er, and their relation tu cancer. J Gascroenterol. 1994;29:61-65. 20. Majeski ]A. Polyps of the gallbladder. J Surg Oncol. 1986;32: 16-18. 21. Katoh T, Nakai T, Hayashi S, et al. Noninvasive carcinoma of the gallbladder arising m localized type adenomyomatosis. Am J Gastroenterol. 1988;83:670-674. 22. Kurihara K, Mizuseki K, Ninomiya T, et al. Carcinoma of the gallbladder arising in adenomyomatosis. Acta Pathol Jpn, 1993;43: 82-85. 23. Kimura W, Shimada H, Kuroda A, et al. Carcinoma of the gallbladder and extrahepatic bile duct in autopsy cases of the aged, with special reference to its relationship to gallstories. Am J Gnstroenterol. 1989;84:386-390.
JOURNAL
OF SURGERYa
VOLUME
175
FEBRUARY
1998
117
Indications for Small Polypoid Lesions of the Gallbladder
Shinkai,
MD, Wataru
Kimura, MD, Tetsuichiro
BACKGROUND: To determine which polyps of the gallbladder should be operated upon, we investigated the size and number of polyps in resected gallbladders, and studied changes in gallbladder polyps using ultrasonography (US). METHODS: We studied 74 resected gallbladders with small polypoid lesions less than 20 mm in diameter, and 60 patients with gallbladder polyps by US. The polyps in resected gallbladders were classified into four groups histologically, and clinical features, maximum diameter, and number of lesions were compared among the groups. In the followed-up cases with gallbladder polyps, the size and number of polyps were examined by US, and changes during the observation period were studied. RESULTS: The mean diameter of adenoma was 6.00 k 3.39 mm (mean rl: SD) and that of cancer 10.6 -c 4.16 mm; 97% of cholesterol polyps were less than 10 mm in diameter (3.66 f 2.66 mm). Neoplastic polyps tended to be single (adenoma, n = 1.40 f 0.89; cancer, n = 1.16 +- 0.40), whereas half of the cholesterol polyps were multiple (n = 3.09 -+ 3.31). However, when there were fewer than 3 lesions, the incidence of neoplasm was 37% among polyps 5 to 10 mm in diameter. A low incidence (6%) of neoplasm was also observed among polyps less than 5 mm in diameter. CONCLUSIONS: These data indicate that an aggressive surgical approach for small gallbladder polyps is warranted when there are fewer than 3 polyps, regardless of their size. Am J Surg. 1998;175:114-117. 0 1998 by Excerpta Medica, Inc.
I
t is well known that most benign polypoid lesions in the gallbladder are cholesterol polyps.’ Ultrasonography (US) is considered to be useful for differentiating malignant from benign lesions, since the specificity of US in the diagnosis of gallbladder polyps is 93.9%.* In addition, by using endoscopic US (EUS), even large cholesterol polyps larger than 10 mm in diameter can be diagnosed correctly based on the characteristic aggregation of echo-
Muto, MD,
Tokyo, Japan
genie spots in the p01yps.~ On the other hand, the early diagnosis of gallbladder cancer before surgery is difficult4-6 and long-term survival is most often expected in cases in which an unsuspected carcinoma is resected for treatment of cholecystolithiasis.7 Therefore, we should try to more precisely differentiate benign polypoid lesions of the gallbladder from malignant lesions. In the present study, we investigated the size and number of polypoid lesions in resected gallbladders, and studied the changes in gallbladder polyps in cases followed by US to determine which gallbladder polyps should be surgically resected.
MATERIAL
AND METHODS
Resected Gallbladders with Polypoid Lesions less than 20 mm in Diameter From January 1980 to December 1995, 667 cholecystectomies were performed for hepatobiliary or other diseases at the First Department of Surgery, Faculty of Medicine, University of Tokyo. Of these 667 resected gallbladders, 74 (11%) had small polypoid lesions less than 20 mm in diameter. The polypoid lesions were classified into four groups histologically: cholesterol polyp, adenoma, cancer, and other. “Other” lesions consisted of hyperplastic polyp, granulation, and adenomyomatosis in the form of a polypoid lesion. Clinical features such as age, gender, cholecystolithiasis, and the maximum diameter and number of lesions were compared among the four groups. Cases with more than 10 lesions were considered to have 10 lesions for analysis purposes. Gallbladder Polyps Followed-up Using Ultrasonography From January 1990 to October 1995, 60 patients with gallbladder polyps were followed up by US. Thirty-five patients were males and 25 were females. The polyps were diagnosed ultrasonographically as cholesterol polyps or benign polyps, and did not include lesions that suggested neoplasms because they should have been excised immediately. The maximum diameter and the number of polyps were examined by US, and changes during the observation period were studied. All results are presented as the mean t SD. Statistical significance was determined at P co.05 by the Wilcoxon test.
RESULTS From the First Department of Surgery, University of Tokyo, Tokyo, Japan. Requests for reprints should be addressed to Hiroshi Shinkai, LID, First Department of Surgery, University of Tokyo, 7-3-l iongo, Bunkyo-ku, , Tokyo 113, Japan. Manuscript submitted October 25, 1996 and accepted in rerised form April 29, 1997.
114
0 1998 by Excerpta All rights reserved.
Medica,
Inc.
Resected Gallbladders with Small Polypoid Lesions The clinical features of the 74 patients are shown in Table I. Cholesterol polyps were found in 44 (59%) cases, adenomas in 5 (7%) cases, cancers in 6 (8%) cases, and other conditions in 19 (26%) cases. Although the mean age of patients with adenoma (44.8 t 15.5 years) tended to be less than those in the other groups, these differences 0002-961 O/98/$1 PII SOOO2-9610(97)00262-6
9.00
1 SURGICAL
I
TABLE
INDICATIONS
FOR
GALLBLADDER
POLYPOID
LESIONS/SHINKAI
ET AL
I Clinical
Type of Lesion Cholesterol POlYP n = 44 (59%) Adenoma n = 5 (7%) Cancer n = 6 (8%) Other n = 19 (26%)
Features
Age (Y) (Mean f SD)
of Cases Gender (MS)
of Small
Polypoid
2 13.4
1:0.91
12 (27%)
44.8
2 15.5
1 :1.5
1 (20%)
in 74 Resected
Gallbladders Number
Maximum Diameter (mm, Mean + SD)
Gallstones
54.3
Lesions
Mean
-c SD
3.66
? 2.68
3.09 + 3.31
6.00
z 3.39 ‘I t
1.40 + 0.89
I
of Lesions Solitary
Multiple
50%
50%
80%
20%
83%
17%
76%
24%
W)
VW
* 59.8 57.0
2 13.9 2 11.8 WY
The maximum diameter of cholesteroipolyp hand, other lessons and neoplastic polyps
1:2.0 1:0.90
3 (50%)
10.83
11 (58%)
5.65
*
k 4.16
1
l
1.16 + 0.40
*
t
t 4.06
1.31 t 0.67
U’JS)
was iess than 5 mm (3.66 2 2.68 mm). and ha/f of them were mu/t!pie with a mean of 3.09 2 3.3 I /es/ox tended to be single, and the number of lesions in cancer cases was almost 1.OO (1.16 t 0.40).
On the other
* P 10.05. t P <0.0001. NS = not significant.
were not significant. Male:female ratios were about 1:0.9 for nonneoplasms (cholesterol polyp and other), whereas there were more females than males among patients with neoplasms (adenoma and cancer). Again, this difference was not significant. The incidence of cholecystolithiasis was highest (58%) in the other group and lowest (27%) in the cholesterol polyp group (P ~0.05). In neoplastic polyps, gallstones were present in 50% of cancer and in 20% of adenomas (not significant). The maximum diameter of cholesterol polyp was less than 5 mm (3.66 ? 2.68 mm). Other lesions (5.65 * 4.06 mm) and adenoma lesions (6.00 ? 3.39 mm) were larger than cholesterol polyp, and the mean diameter of cancer lesions was more than 10 mm (10.8 t 4.16 mm). Almost all (97%) cholesterol polyps were less than 10 mm in diameter, and 82% were smaller than 5 mm. The number of lesions in each group also differed. Half of the cholesterol polyps (50%) were multiple with a mean of 3.09 ? 3.31 lesions. On the other hand, other lesions and neoplastic polyps tended to be single, with means of 1.31 -’ 0.67 and 1.40 2 0.89, respectively. The number of lesions in cancer cases was almost 1.00 (1.16 t 0.40). In adenoma, only 1 case (20%) had multiple polypoid lesions in the gallbladder, which consisted of one adenoma (7 mm) and two cholesterol p01ps (each 2 mm). One case in the cancer group (17%) showed two lesions (10 mm, 4 mm), both of which were polypoid carcinomas histologically. The relationship between the size and the number of polypoid lesions in the present study is shown in the Figure. In summary, cholesterol polyps were usually less than 10 mm in diameter, and polypoid lesions larger than 10 mm in diameter were frequently neoplasms. All of the cases with 4 or more polyps in the gallbladder were cholesterol polyps. When the number of lesions was less than 3, the incidence of neoplasm was 37% among polyps 5 to 10 mm in diameter. A low incidence (6%) of neoplasm was also observed with polyps less than 5 mm in diameter. THE AMERICAN
lb maximum
Figure. cording lesions
diameter
of polypoid
The incidence of neoplasms to the maximum diameter in resected gallbladders.
1'5 lessons
and cholesterol and the number
polyps acof polypoid
Gallbladder Polyps Followed up by US The 60 patients consisted of 35 males and 25 females who ranged in age from 28 to 74 years. There was no difference in mean age between males (50.5 + 11.4 years) and females (53.1 2 12.4 years). Cholecystolithiasis was detected in 5 cases (S%), wall thickness in 4 (7%), and cholesterolosis in 4 (7%) by US. Overall changes in the maximum diameter and number of lesions are shown in Table II. At the first examination, the mean diameter was 4.80 * 2.9 mm and the average number of lesions was 2.06 ? 2.2. After a mean observation period of 22.2 month ( 1 month to 9 years), neither the size nor the number of lesions changed significantly. The maximum increase in diameter was +4 mm (2 cases) over 5 months and 30 months, respectively. Overall, laparoscopic cholecystectomies were performed in 9 patients after a mean observation period of 13.1 months. The presence of symptoms or an increase in size was one of the reasons for operation in these 9 patients. However, most of them had hoped to be operated on, with informed consent, concerned about the gallbladder polyps. Seven of these cases were histologically diagnosed as cholesterol polyps, 1 as iadenoma (3 mm, solitary), and 1 as dysplasia (2 mm, solitary). JOURNAL
OF SURGERYe’
VOLUME
175
FEBRUARY
1998
115
IJRGICAL
INDICATIONS
FOR
GALLBLADDER
POLYPOID
LESIONWSHINKAI
TABLE II Changes in Maximum Diameter and Number of Lesions in 60 Cases with Gallbladder Polyps Followed up by Ultrasonography Maximum Diameter of Polyps (mm) (Mean f SD) At first examination At final examination
4.80 4.33
1 2.9 1 3.2 VW
After a mean obsewatlon the size nor the number NS = not significant.
Number of Polyps (Mean f SD) 2.06 2.26
+ 2.2 + 2.9 VW
period of 22.2 months (1 month of lesions changed significantly.
to 9 years),
nerther
COMMENTS Gallbladder polyps are common in the general population. The prevalence was 4.6% among men and 4.3% among women in a random population in Denmark.” However, among healthy Japanese, that was found to be 6.28% among men, significantly higher than the 3.51% in women, and the racial differences deserved further consideration.” There are several comparisons of the size and number of polyps in benign and malignant lesions. 1,2.1o-1i Most authors believe that malignancy should be suspected or that surgical treatment should be indicated when the polyp is more than 10 mm in diameter and/or when the polypoid lesion is solitary. In the present study, 82% of cholesterol polyps were less than 5 mm in diameter, and 97% were less than 10 mm in maximal diameter. We have not experienced cholesterol polyps or inflammatory polyps over 15 mm in diameter, whereas we have encountered many polypoid lesions more than 20 mm in diameter among neoplasms. Therefore, we always consider gallbladder polyps over 15 mm in diameter to be neoplasms. Although half of the cholesterol polyps in this study were multiple and neoplasms tended to be single, there were also many solitary chopolyps including lesterol polyps (50%) and multiple nroplasms. These results suggest that even if polypoid lesions are less than 5 mm in diameter, or even if the lesions are multiple, neoplastic polyps may be present if there are fewer than 3 polyps. In the cases with gallbladder polyps that we followed up by US, the overall average size and number of lesions did not change. Ukai et al’” reported a case of cholesterol polyp that showed a 40% increase in diameter over 10 months. However, similar cases are infrequent, and most cholesterol polyps do not change in either size or number. Compared with the resected cholesterol polyps, the followed-up polyps were larger in diameter and fewer in number. This can be explained in part by the fact that small polyps that can be found in resected specimens are sometimes not detected by US. None of the 9 patients who underwent surgery after follow-up by US had polypoid cancer, but 1 case of adenoma was found. Although adenoma is not a malignant neoplasm, the premalignant potential of gallbladder adenoma and the adenoma-carcinoma sequence are unquestionable.5,‘7-1’ In addition, adenomyomatosis of the gallbladder has recently been suggksted to have malignant poten116
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gallbladder polyps should be opertial. 5.20-22 Naturally, ated upon when the lesion is suspected to be neoplasm, such as a sessile lesion.“,‘5 In addition, adenomas or inflammatory polyps may also be considered as candidates for resection as premalignant polyps. On the other hand, cholecystolithiasis was frequently found among polyps classified as other or cancer lesions in the present study. Many cases of other lesions were inflammatory, and it is likely that gallstones caused the inflammation. The high incidence of cholecystolithiasis in cancer lesions may suggest a relationship between cancer and gallstones, as previously reported.” Although the present study population was too small to evaluate this relationship, these results indicate that gallbladder polyps with cholecystlithiasis should be removed. In the present cases with cholesterol polyps that we observed, the size and number of lesions did not change. Therefore, follow-up by US is still significant as a means of distinguishing those patients who should be operated upon from those who merit continued observation. However, early cholecystectomy is recommended for gallbladder polyps in order to Identify the early or unsuspected gallbladder cancer. In conclusion, an aggressive surgical approach for small gallbladder polyps is warranted when there are fewer than 3 polyps, regardless of their size.
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