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provided by Elsevier - Publisher Connector HPB, 2005; 7: 155–158

Ultrasonography in the diagnosis of true polyps: the contradiction in the literature

: NUSRET AKYU¨ REK, BU¨ LENT SALMAN, OKTAY IRKO¨ RU¨ CU¨ , MUSTAFA S¸ARE & ERTAN TATLICIOG˘ LU

Medical School of Gazi University, Department of General Surgery, HPB Surgery Unit, Ankara, Turkey

Abstract Polypoid lesions of the gallbladder (PLGs) are often incidentally identified during ultrasonographic examination of abdominal pain. The present study was designed to determine the reliability of ultrasonography (US) in the diagnosis of PLGs. The records of 853 patients who underwent laparoscopic cholecystectomy (LC) for PLGs in Gazi Medical School from January 2000 to January 2004 were reviewed. Data were collected regarding the patients’ gender, age, symptoms, serum lipid levels, the size and the number of polyps on US, surgical indications for PLGs and histopathological diagnosis. In all, 56 of 853 patients had PLGs and underwent LC. Right upper quadrant pain (59%) was the most common presenting symptom that led to gallbladder US. Nearly 75% of the lesions were smaller than 10 mm. At histopathologic examination cholesterolosis was found in 17 of 56 (30%) patients, and 12 of 56 (21%) demonstrated only cholelithiasis; 17 (30%) patients had both cholesterolosis and stones. Only 10 (18%) patients had adenomatous and 8 of these polyps were larger than 1 cm. Overall US-based diagnosis of gallbladder polyp was inaccurate in 82%. The sensitivity and specificity of US for polyps51cm was 20% and 95.1%, respectively, whereas the sensitivity and specificity of US for polyps 41 cm was 80% and 99.3%, respectively. The accuracy of US in diagnosing PLGs was poor, especially in polyps 51 cm.

Key Words: Gallbladder polyp, ultrasonography, laparoscopic cholecystectomy

Introduction screening for other abdominal diseases has increased the detection rate of PLGs. Once identified, they pose a Polypoid lesions of the gallbladder (PLGs) are defined dilemma with respect to their proper long-term as masses protruding from the mucosal surface of the management [6]. Physicians interpreting US reports gallbladder. These lesions, as reported in the literature, describing PLGs must understand the accuracy and range from 1.3% to 6.9% in both genders [1–3]. PLGs significance of this US finding, as it could affect the can be benign or malignant. In 1958, Carrera and determination of the necessity for cholecystectomy. Oschsner [4] evaluated polyps taken from more than The present retrospective study was designed to 1300 cholecystectomies and described five types of determine the reliability of US in the diagnosis of mucosal polypoid lesions: inflammatory, cholesterol, PLGs. The literature was also reviewed for current adenoma, adenomyoma, and carcinoma. In 1970, diagnostic modalities for PLGs. Christensen and Ihsak [5] evaluated 180 gallbladder lesions at the Armed Forces Institute of Pathology. In addition to the categories described by Carrera and Patients and methods Oschsner, they also noted two granular cell tumors of the cystic duct and seven polyps of gastric heterotopic The records of patients who underwent laparoscopic tissue. PLGs are usually diagnosed with ultra- cholecystectomy (LC) with an US report showing sonography (US) as nonshadowing, fixed, solid PLGs in our institution from January 2000 to January masses. Symptoms are unusual unless other abnormal- 2004 were reviewed and data were collected regard- ities, such as stones, are present. The widespread use ing patients’ gender, age, symptoms, serum choles- of US in patients with suspected and terol levels, serum low-density lipoprotein (LDL)

Correspondence to: Nusret Akyu¨rek, MD, Gazi University, School of Medicine, Department of General Surgery, HPB Surgery Unit, 06500 Ankara, Turkey. Fax:+90 312 2124647 and +90 312 2230528. Tel: +90 312 2025746. E-mail: [email protected]

ISSN 1365-182X print/ISSN 1477-2574 online # 2005 Taylor & Francis Group Ltd DOI: 10.1080/13651820510003762 156 N. Akyu¨rek et al. Table I. Clinical and demographic data of patients with gallbladder polyp on preoperative US.

Patients Characteristic (n=56)

Age (years), median and range 48.0 (24–66) Sex (male/female) 40/16 Laboratory data Serum cholesterol (U/L) mean+SD 160.2+15.3 Serum HDL (U/L) mean+SD 42.1+10.2 Serum LDL (U/L) mean+SD 65.3+14.1 Serum triglyceride (U/L) mean+SD 70.4+22.2 Symptoms Asymptomatic (%) 6 (11) Right upper quadrant pain (%) 33 (59) Nausea (%) 23 (41) Epigastric discomfort (%) 18 (32) Others (%) 10 (18) Figure 1. Cholesterol polyp of the gallbladder. Ultrasonography Indications shows a 12-mm, granular-surfaced pedunculated mass with an Any symptomatic patients (%) 49 (87) internal echo pattern characterized as an aggregation of echogenic Enlarging size of polyp (%) 6 (11) spots with scattered echopenic areas. Concomitant cholelithiasis (%) 1 (2) cholesterol levels, serum high-density lipoprotein and 16 men; the median age was 48.0 years (range (HDL) cholesterol levels, serum triglyceride levels, the 24–66). All the patients in this study had a preoperative size and the number of polyps on US, surgical indica- ultrasonographic examination. The interval between tions for PLGs and pathologic evaluation of the gall- the US study and LC ranged from 1 to 23 months bladder. (median 7 months). Eight (14%) of the 56 patients A 3.5-MHz linear-array transducer attached to an were asymptomatic and their PLGs were detected on EUB-420 scanner (Hitachi, Tokyo, Japan) was used US during a check-up. The remaining 48 (86%) for the ultrasonographic examinations. The patients patients had symptoms, which led to ultrasonographic fasted overnight for 8 h, and then multiple scans were examination. Right upper quadrant pain (59%) was done with the patients supine and in left lateral decu- the most common presenting symptom that led to bitus position. To ensure that the lesions were not gallbladder US. The other symptoms were nausea mobile, additional scans were made with the patients in (41%), epigastric discomfort (32%), flatulence (22%), different positions such as sitting or standing. PLG was and food intolerance (15%). In the US study, the defined on US as a lesion projecting into the lumen of diameter of the polyp measured 0–5 mm in 22 the gallbladder which did not cast an acoustic shadow patients, 6–10 mm in 20 patients, and 410 mm in 14 and did not move with the position of the patient patients. Hepatosteatosis was seen only in one patient (Figure 1). When two or more polyps were identified, and only that patient had high serum cholesterol and the size of the larger polyp was used for analysis. All LDL levels. Serum LDL, HDL, triglyceride and scans were performed by radiologists with special cholesterol levels were in normal ranges in patients training in abdominal US. with PLGs. On preoperative ultrasonographic evalua- Three months after undergoing an uneventful LC, a tion 10 patients had multiple polyps and all of them face to face interview was carried out to determine were 4–7 mm in diameter. Indications for cholecys- whether the symptoms had resolved in patients with tectomy in patients with PLGs were symptomatic gallbladder polyp on preoperative US. (n=49), enlarging size of polyp between serial ultrasonograms (n=6), and concomi- Statistical analysis tant cholelithiasis (n=1). The characteristics of the patients are listed in Table I. The sensitivity, specificity, positive predictive value At histopathologic examination cholesterolosis was (PPV) and negative predictive value (NPV) of US for seen in 17 of 56 (30%) patients, and 12 of 56 (21%) gallbladder polyps were calculated. Mean and standard demonstrated only cholelithiasis; 17 (30%) patients deviations (SD) of the data were also calculated when had both cholesterolosis and stones. Only 10 patients necessary. had an adenomatous polyp and 8 of these were 41cm in diameter. No malignancies were identified (Table II). The remaining 797 patients had only cholelithiasis Results on preoperative US. On the other hand, pathological The records of 853 patients who underwent elective examinations revealed that 10 of these patients also had LC in our institution were reviewed. This revealed that various types of polyps (Table III). No malignancy was 56 of 853 patients had PLGs. There were 40 women seen in these patients. Ultrasonography in diagnosis of true gallbladder polyps 157 Table II. Histopathological diagnosis and maximal diameter of Table IV. The sensitivity and specificity of US for patients with polypoid lesions. PLGs.

Polyp diameter on US Parameter Polyps 51 cm Polyps 41cm Histopathological diagnosis 56 mm 6–10 mm 410 mm Total (%) Sensitivity (%) 20 80 Specificity (%) 95.1 99.3 Cholesterolosis 10 6 1 17 (30) PPV (%) 4.76 57.14 Cholelithiasis 5 5 2 12 (22) NPV (%) 98.99 99.74 Cholesterolosis and 6 8 3 17 (30) cholelithiasis PPV, positive predictive value; NPV, negative predictive value. Adenomatous polyp 1 1 8 10 (18) Total 22 20 14 56 (100) 94% sensitivity of US for detecting PLGs. On the other hand Damore et al. [9] reported that US-based diag- During the follow-up period, a face to face interview nosis of PLGs was inaccurate in 95% of patients was carried out with 41 of 49 patients who underwent undergoing cholecystectomy. In this study the follow- LC because of symptomatic gallbladder polyp. Eight ing ultrasonographic criteria were used for the diag- patients did not reply to the invitation. The symptoms nosis of polyps. (1) An image with similar echogenicity resolved in 38 (92.6%) of these 41 patients. The to the gallbladder wall that projects to lumen, (2) fixed histopathological examination of enlarging polyps image, (3) lacks displacement, and (4) lacks an between serial ultrasonograms revealed that five of six acoustic shadow. To differentiate an impacted stone patients had adenomatous polyps and one had chole- that can mimic a polyp on US, scanning was performed thiasis with cholesterolosis. The sensitivity and speci- after repositioning the patient in the prone or right ficity of US for polyps 51 cm was 20% and 95.1%, lateral decubitis position. This makes it technically respectively. On the other hand, the sensitivity and easier to prove the presence of a stone, because repo- specificity of US for polyps 41 cm was 80% and sitioning the patient causes the stone to move. A 99.3%, respectively (Table IV). combination of stones and cholesterolosis may mimic PLGs. Echoes produced by gallstones are usually high in amplitude; however, occasionally they are less Discussion echogenic than expected. This appearance occurs most often in patients with soft stones that have mud-like Conventional US is routinely used to evaluate the consistency, as seen in patients with cholesterolosis. gallbladder. During ultrasonographic examination, the Additionally, a impacted in the gallbladder nonshadowing single or multiple fixed masses that wall that is located in a dependent position can give the project into the lumen of the gallbladder are regarded appearance of a small PLG. as PLGs [1,7]. The polyps can be neoplastic The differences in the findings between gallbladder (adenoma, cancer) or non-neoplastic (cholesterol US and gallbladder pathology reports are related to polyp, inflammatory). Surgeons and other physicians several factors. It was very difficult to diagnose PLGs need to be aware of the significance of PLGs noted on on the basis of the size of lesion. A number of papers the ultrasonogram. Preoperative correct diagnosis is have reported that diagnosis of PLGs 510 mm mandatory for decisions regarding surgery. The remains difficult in many cases [10–12]. In the present present study demonstrated that US-based diagnosis study, histopathological examination revealed only two of PLGs was inaccurate in 82% of patients. There is a true polyps in patients who had PLG 510 mm on disagreement in the literature concerning the accuracy preoperative US. Strikingly, 14 patients had PLGs of US in diagnosing PLGs. Yang et al. [8] reported a 410 mm on preoperative US and at histopathological examination 8 of them were true polyps. In this study, Table III. Histopathological findings of PLGs that were missed on the sensitivity and specificity of US for polyps 51cm preoperative US. was 20% and 95.1%, respectively. On the other hand, the sensitivity and specificity of US for polyps 41cm Age Permanent histopathologic was 80% and 99.3%, respectively. (years) Gender examination Size (mm) Cholesterolosis of the human gallbladder is a 44 Male 4 common disease and its reported prevalence has varied 52 Female 3 from 9% to 24% [13,14]. Cholesterolosis is char- 55 Female Inflammatory polyp 4 acterized histologically by the accumulation of lipids in 48 Female 5 51 Female 5 the lamina propria of the gallbladder. These lipid 56 Male Gastric heterotopic tissue 5 deposits consist mostly of cholesterol ester and tri- 43 Female 4 glycerides [15]. The etiology of cholesterolosis is not 35 Female 12 yet fully understood. In this study cholesterolosis was 46 Female Adenomatous polyp 11 seen in 34 of 56 (61%) patients and we did not find any 54 Female 4 correlation between serum LDL, HDL, triglyceride 158 N. Akyu¨rek et al. and cholesterol levels and cholesterolosis. Similar to References our findings, Mendez-Sanchez et al. [16] reported [1] Jorgensen T, Jensen KH. Polyps in the gallbladder: a prevalence that cholesterolosis is not associated with high choles- study. Scand J Gastroenterol 1990;25:281–6. terol levels in patients with and without gallstone [2] Chen CY, Lu CL, Chang FY, Lee SD. Risk factors for gall- disease. Also, Watanabe et al. [13] suggested that bladder polyps in the Chinese population. Am J Gastroenterol cholesterol ester synthesis of gallbladder mucosa might 1997;92:2066–8. play an etiological role in the development of choles- [3] Ozmen MM, Patankar RV, Hengirmen S, Terzi MC. Epi- demiology of gallbladder polyps. Scand J Gastroenterol terolosis. 1994;29:480. The ultrasonographic technology continues to [4] Carrera GM, Oschsner SF. Polypoid mucosal lesions of improve and endoscopic ultrasonography (EUS) gallbladder. JAMA 1958;166:888–92. seems to be superior to conventional US for imaging [5] Christensen AH, Ihsak KG. Benign tumors and pseudotumors the gallbladder. US can demonstrate various polypoid of the gallbladder. Arch Pathol 1970;90:423–32. [6] Rosin RD. Laparoscopic cholecystectomy. In: Zinner MJ, lesions of the gallbladder; however, the differential Schwartz S, Ellis H, eds. Maingot’s abdominal operations. New diagnosis of polypoid lesions 510 mm remains diffi- York: Appleton & Lange; 1997. 1864–5. cult in many cases. US is limited as a diagnostic tool, if [7] Berk RN, van der Vegt JH, Lichtenstein JE. The hyperplastic the diagnosis depends solely on the shape and surface cholecystoses: cholesterolosis and adenomyomatosis. Radi- characteristics of the polypoid lesions. In contrast, ology 1983;146:593–601. [8] Yang HL, Sun YG, Wan Z. Polypoid lesion of the gallbladder: EUS can provide information not only about the diagnosis and indications for surgery. Br J Surg. 1992;79: morphology and surface features, but also the internal 227–9. echo status of the polyp. The internal echo of a true [9] Damore LJ II, Cook CH, Fernandez KL, Cunningham J, polyp is usually hypoechoic to isoechoic and almost Ellison EC, Melvin WS. Ultrasonography incorrectly diagnoses homogenous, if not slightly heterogeneous. EUS can gallbladder polyps. Surg Laparosc Endosc Percutan Tech 2001;11:88–91. readily image the layer structure of gallbladder wall [10] Azuma T, Yoshikawa T, Araida T, Takasaki K. Differential and provide high-resolution images of small lesions diagnosis of polypoid lesions of the gallbladder by endoscopic [10,17,18]. Once a polyp of the gallbladder has been ultrasonography. Am J Surg 2001;181:65–70. identified by standard US, the next question comes [11] Koga A, Watanabe K, Fukuyama T, Takiguchi S, Nakayama F. to mind: ‘Is this benign or malignant?’. Judging Diagnosis and operative indications for polypoid lesions of the gallbladder. Arch Surg 1988;123:26–9. from the US diagnostic results in the present study, [12] Kubota K, Bandai Y, Noie T, Ishizaki Y, Teruya M, Makuuchi for patients with polyps 510 mm in size, EUS M. How should polypoid lesions of the gallbladder be treated in should be conducted for differential diagnosis. If the era of laparoscopic cholecystectomy? Surgery 1995;117: patients with PLGs are asymptomatic, it is particularly 481–7. important to differentiate between benign and malig- [13] Watanabe F, Hanai H, Kaneko E. Increased acylCoA-choles- terol ester acyltransferase activity in gallbladder mucosa in nant lesions, because implementation of surgery patients with gallbladder cholesterolosis. Am J Gastroenterol depends on the differentiation. Therefore, when it 1998;93:1518–23. is difficult to differentiate between malignant and [14] Jacyna MR, Ross PE, Bakar MA, Hopwood D, Bouchier IA. nonmalignant US-detected gallbladder polyps in Characteristics of cholesterol absorption by human gall blad- asymptomatic patients by US alone, EUS could be der: relevance to cholesterolosis. J Clin Pathol 1987;40:524–9. [15] Tilvis RS, Aro J, Strandberg TE, Lempinem M, Miettinen TA. best applied. Therefore, EUS is thought to play an Lipid composition of bile and gallbladder mucosa in patients important role in determining the treatment strategy with acalculous cholesterolosis. Gastroenterology 1982;82: for PLGs. 607–15. A recent study assessed the use of positron emission [16] Mendez-Sanchez N, Tanimoto MA, Cobos E, Roldan-Valadez tomography (PET) scanning using F-labelled deoxy- E, Uribe M. Cholesterolosis is not associated with high cholesterol levels in patients with and without gallstone disease. glucose (FDG) and the authors reported that FDG- J Clin Gastroenterol 1997;25:518–21. PET may become one of the most useful tools for [17] Sugiyama M, Xie XY, Atomi Y, Saito M. Differential diagnosis accurate preoperative diagnosis of small PLGs [19]. of small polypoid lesions of the gallbladder. Ann Surg Helical computed tomography seems to be another 1999;229:498–504. alternative method for differentiating neoplastic and [18] Kimura K, Fujita N, Noda Y, Kobayashi G, Ito K. Differential diagnosis of large-sized pedunculated polypoid lesions of the non-neoplastic small PLGs [20]. gallbladder by endoscopic ultrasonography: a prospective Taking into account the inaccuracy of US in the study. J Gastroenterol 2001;36:619–22. diagnosis of PLGs, patients with symptomatic PLG [19] Koh T, Taniguchi H, Kunishima S, et al. Possibility of differ- should be offered laparoscopic cholecystectomy. ential diagnosis of small polypoid lesions in the gallbladder Asymptomatic patients with PLGs, especially lesions using FDG-PET. Clin Pos Imag 2000;3:213–18. [20] Frukawa H, Kosuge T, Shimada K, Yamamoto J, Kanai Y, 51 cm, should rescanned. If the lesion increases in size Mukai K, et al. Small polypoid lesions of the gallbladder: between serial ultrosonograms, they should once again differential diagnosis and surgical indications by helical be offered surgery. computed tomography. Arch Surg 1998;133:735–9.