Distinguishing between acute appendicitis and appendiceal mucocele ...

Eur J Trauma Emerg Surg (2013) 39:523–529 DOI 10.1007/s00068-013-0321-3

ORIGINAL ARTICLE

Distinguishing between acute appendicitis and appendiceal mucocele: is this possible preoperatively? B. Saylam • C. E. Gu¨ldog˘an • F. Cos¸ kun V. Vural • B. C ¸ omçalı • M. Tez

•

Received: 27 November 2012 / Accepted: 12 August 2013 / Published online: 24 August 2013 Ó Springer-Verlag Berlin Heidelberg 2013

Abstract Purpose Mucocele of the appendix is an infrequent event, characterized by a cystic dilatation of the lumen. It is often diagnosed clinically from signs and symptoms of acute appendicitis or, if it is asymptomatic, as an incidental finding during ultrasonography, computed tomography, or laparotomy. Methods We evaluated the histological data of patients who were believed to have mucocele of the appendix. These patients (n = 23) were compared with sex- and agematched control subjects (n = 79) with appendicitis. Results The main reason for emergency surgery was lower right abdominal pain in 15 patients, and intestinal obstruction in three. Univariate analysis using sonography demonstrated that the larger appendiceal outer diameter was positively correlated with the diagnosis of appendiceal mucocele (p = 0.001) and the mean white blood cell count

B. Saylam C. E. Gu¨ldog˘an F. Cos¸ kun V. Vural B. Çomçalı M. Tez Department of Surgery, Ankara Numune Training and Research Hospital, Ankara, Turkey e-mail: [email protected] F. Cos¸ kun e-mail: [email protected]

was negatively correlated (p = 0.023). In urine analysis, 41.7 % of the mucocele patients and 10 % of the appendicitis patients had microscopic hematuria, respectively (p = 0.019). An outer diameter of 10 mm or more was predictive of appendiceal mucocele diagnosis, with a sensitivity of 76.5 %, specificity of 81 %, positive predictive value of 76.5 %, and negative predictive value of 94.12 %. The overall diagnostic accuracy was 80.2 %. One point was given for the presence of each of these factors to develop a new score. The resulting area under the receiver operator characteristic curve was 0.855 (95 % CI 0.741–0.969) for the score. The histological examination of the specimens revealed mucocele in 15 cases, mucinous cystadenoma in seven cases and mucinous cystadenocarcinoma in one case. Twenty patients underwent appendectomy, and three patients were treated with right colectomy. Conclusions A threshold 10-mm diameter of the appendix under compression is a useful preoperative measurement for differentiating between appendiceal mucocele and acute appendicitis. Microhematuria is simple test that can provide a significant role in supporting the clinical diagnosis of appendiceal mucocele in the emergency department. Keywords Mucocele of the appendix Appendicitis Score Microhematuria

V. Vural e-mail: [email protected] B. Çomçalı e-mail: [email protected]

Introduction

M. Tez e-mail: [email protected]

Mucocele of the appendix (AM) is a rare disease, characterized by an obstructive dilatation of the appendix with mucus inside. Mucocele of the appendix is a descriptive term for several pathological processes. They include simple retention mucoceles arising from obstructed outflow, mucoceles with hyperplastic epithelium, the most

B. Saylam (&) Genel Cerrahi Klinig˘i, Ankara Numune Hastanesi, Talatpas¸ a Bulvarı, 06100 Altındag˘, Ankara, Turkey e-mail: [email protected]

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to detect an odds ratio (OR) of 0.7 based on 80 % power, 5 % significance level, a correlation between matched cases and controls of 0.1, with an average of four controls per case.

common variant of mucinous adenoma or cystadenoma, and, finally, malignant mucinous cystadenocarcinoma [1]. It can be an asymptomatic finding or it can present with complications. The most feared complication is pseudomyxoma peritonei, which is difficult to treat and carries an uncertain prognosis whether the mucocele originates in benign or malignant disease: its 5-year survival rate is only 53–75 % [2]. An association between appendiceal mucocele and synchronous neoplasms has been previously noted [3]. The most common synchronous neoplasms occur in the large bowel, although they can also be found in other locations, such as the endometrium, bladder, ovary, and prostate [3, 4]. Accurate preoperative diagnosis and prompt surgical intervention are mandatory because of the possibility of rupture at surgery with the development of pseudomyxoma peritonei and of missing the possible associated intraabdominal tumors. The most common clinical forms of presentation of this entity are: as an incidental finding during another examination, as clinical symptoms of pain or discomfort at the height of the right lower quadrant indicative of acute appendicitis, or as an abdominal mass found in the right iliac fossa [3]. The aim of our study was to determine the factors significantly correlated with AM, via comparison of the clinical and sonographic parameters of AM with those of acute appendicitis in emergency department patients.

Bivariate comparisons of patients with mucocele and those with acute appendicitis were unpaired, and all tests of significance were two-tailed. A comparative analysis of categorical variables was performed using v2 testing with Yates’ continuity correction. Continuous variables were analyzed using Student’s t tests for normally distributed variables; otherwise, the Mann–Whitney U test was used. Logistic regression was used to identify the factors associated with mucocele of the appendix. Results of the multivariate analysis are shown as ORs with 95 % confidence intervals (CI). Receiver operator characteristic (ROC) curve analyses were used to determine the optimal cutoff values for continuous variables. A clinical score based on the final logistic regression model was constructed in which one point was assigned for the presence of each predictive factor. Model discrimination was measured as the area under the ROC curve (AUC). The discrimination of a prognostic model is considered perfect if AUC = 1, good if AUCis [0.8, moderate if AUCis 0.6–0.8, and poor if AUC is \0.6. We used SPSS for Windows 11.5 (Chi. IL., USA) for statistical analysis.

Materials and methods

Results

Subjects

During the 8-year study period, a total of 3,407 patients underwent appendectomy at our center. Of these patients, 23 (0.67 %; 13 men, 10 women; mean age, 56 years; range, 17–82 years) had mucocele of the appendix. Intraoperative findings were simple mucocele in 12 cases, two cases of perforated mucocele showing contamination of mucoid fluid contained in the appendix, seven cases of appendicitis, and two cecal masses. Three synchronous primary neoplasms were identified. Two were in the colorectum, and one in the ovary. In all cases of appendiceal mucinous cystadenomas and cystadenocarcinomas, resection margins at the base of the appendix were negative for malignancy and appendiceal lymph nodes were negative for metastases. The postoperative complications were wound infection in four patients, urinary tract infection in one patient. No immediate postoperative deaths were registered (Table 1). The group of patients with acute appendicitis without mucocele consisted of 48 men and 31 women (mean age, 49 years; range, 31–79 years). In these patients, findings at pathological examination were as follows: acute appendicitis without perforation in 67 cases, perforated acute appendicitis in 12 cases, necrotizing or

A search of the surgery clinic database at the Ankara Numune Research Hospital from January 2004 to May 2012 was performed to identify all patients who had undergone appendectomy with the clinical diagnosis of acute appendicitis or acute abdomen and final diagnosis of mucocele of the appendix. This search yielded 23 patients. Clinical, radiological (ultrasound and/or computerized tomography) and laboratory (complete blood count, liver function tests, urinary function tests and urinalysis) data were obtained from all of the patients. Urinalysis was done on a clean-catch specimen on admission of each patient. The presence of three or more red blood cells per highpower microscopic field in urinary sediment was accepted as microscopic hematuria. We searched the clinical database to identify 79 consecutively registered patients who underwent appendectomy and had pathologically proven acute appendicitis without mucocele. They were matched for age and gender with each AM case. The sample size for this group of patients was determined on the basis of statistical power considerations,

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Statistical methods

Distinguishing between acute appendicitis and appendiceal mucocele

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Table 1 Clinical, perioperative and pathological findings in patients with mucoceles of the appendix Number

Presenting symptoms

Microscopic hematuria

Intraoperative findings

Type of operation

Histologic diagnosis

Presence of synchronous tumor

1

Acute appendicitis

No

Cecal tumor

Right hemicolectomy

Mucinous cystadenocarcinoma

–

2

Acute abdomen

ND

Ruptured ? periappendiceal mucous spread

Appendectomy ? removal of gross implants

Mucinous cystadenoma

–

3

Acute appendicitis

Yes

Gangrenous

Appendectomy

Mucocele

Sigmoid adenocarcinoma

4

Acute appendicitis

No

Acutely inflamed

Appendectomy

Mucocele

–

5

Acute appendicitis

No

Gangrenous

Appendectomy

Mucocele

–

6

Acute abdomen

No

Appendiceal mucocele

Appendectomy

Mucocele

–

7

Acute appendicitis

Yes


Appendectomy

Mucocele

–

8

Acute abdomen

No


Appendectomy ? Right salpingoophorectomy


Right ovary tumor

9

Intestinal obstruction

ND


Appendectomy

Mucocele

–

10

Acute abdomen

Yes

Ruptured ? periappendiceal mucous spread

Right hemicolectomy ? removal of gross implants


Cecal adenocarcinoma

11

Acute appendicitis

ND

Acutely inflamed

Appendectomy

Mucocele

–

12

Acute appendicitis

No

Acutely inflamed

Appendectomy

Mucocele

–

13

Acute appendicitis

No


Appendectomy

Mucocele

–

14


ND

Acutely inflamed

Appendectomy


–

15

Acute appendicitis

Yes


Appendectomy

Mucocele

–

16

Acute appendicitis

ND


Appendectomy

Mucocele

–

17

Acute appendicitis

Yes


Appendectomy

Mucocele

–

18

Acute abdomen

Yes


Appendectomy


–

19

Acute abdomen

ND


Appendectomy


–

20

Acute appendicitis

No


Appendectomy

Mucocele

–

21

Acute appendicitis

Yes

Acutely inflamed

Appendectomy

Mucocele

–

22

Acute appendicitis

No


Appendectomy

Mucocele

–

23


No

Cecal tumor

Right hemicolectomy


–

ND not done

gangrenous appendicitis in 54 cases, and early or mild appendicitis in 25 cases. Nineteen ultrasound (US) studies were performed, six of them suggesting mucocele of the appendix. Twenty patients underwent open appendectomy and three patients underwent right hemicolectomy (in cases where

malignancy was suspected). Pathologic examination revealed mucinous cystadenoma of the appendix in seven cases, mucinous cystadenocarcinoma of the appendix in one case and simple mucocele in 15 cases. The mean white blood cell (WBC) count was higher for patients with simple acute appendicitis compared to those

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with mucocele (13.5 ± 4 9 104 vs. 11.0 ± 5 9 104 lL, p = 0.023). In urinalysis, 41.7 % of the mucocele patients and 10 % of the appendicitis patients had microscopic hematuria respectively (p = 0.019). The maximal outer diameter of the appendix in US examination was significantly greater in mucocele group than the appendicitis group (18.85 ± 12.15 vs. 8.20 ± 2.21 mm respectively, p = 0.001) (Table 2). The maximal outer diameter of the appendix in US had diagnostic value in differentiating between mucocele and acute appendicitis (area under the curve = 0.918, p \ 0.001, 95 % CI 0.854–0.952) (Fig. 1). A 10-mm outer diameter achieved a sensitivity of 76.5 %, specificity of 81 %, positive predictive value of 76.5 %, and negative predictive value of 94.12 % for the diagnosis

of acute appendicitis with mucocele. The overall diagnostic accuracy was 80.2 %. Multivariate risk prediction model and prediction score All of the variables that could be assessed before surgery were included in the multivariate model. Three variables were statistically significant in this analysis: WBC count B11,000/mm3, outer diameter of the appendix [10 mm, and microscopic hematuria (Table 2). A probability score was calculated by adding the number of points assigned to each variable. Although the regression coefficients ranged from 1.75 to 2.78, for the sake of simplicity, one point was assigned to each of these risk factors. The resulting score (WBC count, outer diameter, and microscopic hematuria) ranged from I to III (Table 3). Three groups of patients were defined based on the score. The first group, with a score of I (0 points), comprised about 40 % of the patients whose risk of mucocele was\5 %. The second group included patients with a score of II (1 point), who had an 8 % risk of mucocele; this group comprised of approximately 39 % of the cohort. The third group, which comprised approximately 21 % of the patients, included those with a score of III (C2 points) whose risk of mucocele was [50 % (Table 4). The specificity, sensitivity, positive predictive value, negative predictive value, negative likelihood ratio, and positive likelihood ratio for scores exceeding II were 89.87 %, 73.33 %, 57.89 %, 94.67 %, 0.30, and 7.24, respectively. The area under the ROC curve was 0.855 (95 % CI 0.741–0.969) for the score (Fig. 2).

Discussion The clinical presentation of a mucocele is usually nonspecific. Only 50 % of the patients are symptomatic and in the rest it is an incidental finding at the time of surgery. This presentation varies in emergency departments

Fig. 1 ROC curve analysis of the appendiceal diameter

Table 2 Demographics, sonographic and urinalysis findings in patients with appendiceal mucoceles and with acute appendicitis

Age (years)

Appendiceal mucoceles

Appendicitis

p

56.57 ± 20.7

48.91 ± 15.7

NS

Male (%)

13 (56.5 %)

48 (60 %)

NS

White blood cell counts (9104/lL)a

11.0 ± 5

13.5 ± 4

0.023

Appendiceal outer diameter (mm)a,

18.85 ± 12.15

8.20 ± 2.21

0.001

7 (41.1 %)

8 (10 %)

0.019


b

c

NS indicates nonsignificant a

Expressed as mean ± SD

b

Using recorded apendiceal outer diameter for statistical analysis

c

Using recorded urinalysis for statistical analysis

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Table 3 Multivariate logistic regression model for predictors of the presence of a mucocele

(US), preoperative colonoscopy, and computed tomography (CT) are useful methods in diagnosing mucocele and distinguishing the mucocele from mimicking diseases [6]. However, a diagnosis of underlying tumor is usually made only at the time of surgery or even later, during pathological examination of the surgical specimen [5]. This delay in diagnosis often requires modification of the surgical approach or a second surgical procedure such as right hemicolectomy. In the past, AM was believed to occur more commonly in women than in men [3]. However, recent reports showed a distinct male predominance [7, 8], as in our series. Thus, an analysis of more cases of AM is needed to determine its sex predominance. Appendiceal mucocele is more frequent in individuals over 50 years of age [3, 8]. In this study, 16 of the 23 patients were older than 50 years. In age distribution, our results agree with the literature, although mucocele may be diagnosed at any age. About 69 % of all patients with acute appendicitis in the United States are under 30 years of age [9], whereas only 5 % of patients (four of 79) in our series were under 30 years of age (an age-matched control group). Despite the improvements in imaging tests, a correct preoperative diagnosis was achieved in only 29 % of the cases in the literature [8]. Ultrasound is the first-line diagnostic modality for patients with acute abdominal pain. The graded compression technique involves applying steady, gradual pressure to the right lower quadrant in an effort to collapse the normal bowel and eliminate normal bowel gas to visualize the appendix. An inflamed appendix is noncompressible, enlarged, and immobile. The threshold diameter of 6 mm, which is the most commonly reported threshold, had both high NPV and PPV (98 %) [10]. Different sonographic findings of the AM have been described [7, 11]. On the ultrasonography findings, mucoceles usually appear in the right lower quadrant as an elongated, echo-poor mass without posterior echo enhancement. The cyst wall is less distinct than one would expect for a cyst [7]. An appendiceal outer diameter of 15 mm or more in US examination has been determined as the threshold for AM diagnosis with a sensitivity of 83 % and specificity of 92 % [11]. In our study, unlike previous studies [11], The threshold diameter of 15 mm had a sensitivity of 45 %, specificity 97 %, with a positive predictive value of 81 % and a negative predictive value of 87 %. The most important limitation of our study was the small number of patients with mucocele, which limited the statistical power of comparisons between patients with mucocele and those without. These results also might have been influenced by the small sample size.

Regression coefficient

p

Score points

White blood cell count (B11,000/mm3)

1.75

0.017

1

Appendiceal outer diameter ([10 mm)

2.78

0.0001

1


2.12

0.01

1

Table 4 Risk of mucocele according to the score Score

Number of appendicitis (%)

Number of appendiceal mucocele (%)

I

37 (97.4)

1 (2.6)

II

34 (91.9)

3 (8.1)

III

8 (42.1)

11 (57.9)

Fig. 2 ROC curve analysis of the score

throughout the world. In this study, regarding the symptoms presented, acute pain in the right iliac fossa within a context of acute appendicitis is the most common symptom, found in nearly 60 % (n = 14) of cases. A study done by Stocchi and colleagues found that of patients with symptoms, 27 % had abdominal pain, 14 % had an abdominal mass, 13 % lost weight, 9 % had nausea, vomiting, or both, and 8 % had acute appendicitis. The presence of symptoms was associated with a higher incidence of cystadenocarcinoma [4]. Preoperative detection of an appendiceal neoplasm is important with regard to surgical planning in patients presenting with symptoms of appendicitis [5]. Ultrasonography

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In differentiating acute appendicitis with mucocele from acute appendicitis without mucocele, our results show that the most discriminating US feature is the outer diameter of the appendix. The mean appendiceal luminal diameter of about 19 mm in patients with mucocele in our series agrees with findings in other studies that an overall appendiceal diameter of 15 mm or greater suggests of appendiceal mucocele [11]. In our study, when the maximal luminal diameter of the appendix was greater than 10 mm, the sensitivity was 76.5 % and the specificity was 81 % in the diagnosis of mucocele. Computed tomography has great value in ruling out appendicitis. It can also identify conditions suitable for conservative management such as gynaecological diseases, intra-abdominal fat necrosis and appendiceal abscess [12]. CT is ideal for evaluating mucoceles of the appendix because it has certain advantages over other imaging modalities [5]. However, CT findings in study patients were not examined because most patients did not undergo CT examination. Although CT had a higher diagnostic accuracy, we believe that US should be the primary investigation method for all patients with suspected appendicitis, as others investigators have stated before. Abnormal urinalysis is not uncommon in patients with acute appendicitis. Yamamoto et al. [13] found six cases of microscopic hematuria in 32 patients with appendicitis. In our series, microscopic hematuria in a patient with appendicitis is not uncommon and was found in 10 % of the patients who underwent appendectomy for acute appendicitis. The high incidence of abnormal urinalysis in patients with either a ruptured or inflamed appendix in the retrocecal or pelvic position suggests that the pathological status of the appendix and its proximity to the urinary system may be factors. However, asymptomatic microhematuria is a common finding, occurring in 13 % of adult men and postmenopausal women [14]. Mucocele of the appendix rarely exhibits urologic features. Hydronephrosis, irritative syndrome [15], renal failure [16], invasion locally into the bladder [17], and presentation as cystic renal masses [18] have been described. Hematuria is reported to be a rare presentation of appendiceal mucocele [19–21]. These presentations might be caused by local or mass effects of mucocele of the appendix. The results of the current study showed a higher incidence of microhematuria in patients with appendiceal mucocele compared to the previous reports on a normal population and acute appendicitis. In a meta-analysis by Andersson [22] that included 24 studies and 5,833 patients, the authors reported that WBC [10 was a solid discriminator of appendicitis (?LR = 11.34 [95 % CI 6.65–19.56]). According to reports, WBC count was elevated in 40 and 55 % of all cases and of appendiceal mucocele, respectively [8, 23]. In

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a series of 16 patients with symptoms suggestive of acute appendicitis, those with confirmed appendiceal mucocele had a mean WBC count of 9,315 (per mcL). In contrast, those with appendicitis had a mean WBC count of 12,175 [11]. In the current study, WBC counts were significantly higher for patients with appendicitis compared to patients with appendiceal mucocele. We developed and validated a novel scoring system to predict the risk of AM in patients with the clinical diagnosis of acute abdomen. Other researchers have identified several factors that are associated with an increased risk of AM, but we believe we are the first to have assessed these factors together. For a scoring system to be clinically useful, it must fulfill several criteria: it should use readily available and verifiable clinical information; it should have been developed and validated in the population in which it is to be used; and it should be free from confounding factors. The scoring system developed here uses data that are easily collectable for any patient presenting with acute appendicitis. WBC count B11,000/mm3, outer diameter of the appendix [10 mm, and microscopic hematuria were independent predictors for occult rupture in our study. Using the results of multivariate logistic regression analysis, we developed the scoring system (score range, I–III) to predict AM. A score of III had a sensitivity of 73 %, a specificity of 89 %, and a positive predictive value of 57 % to predict AM. Laparoscopic management of appendiceal mucocele can be performed safely and successfully with certain precautions. Careful patient selection is mandatory to achieve successful results. The main concern regarding its use in dealing with mucinous-secreting lesions is the possible spillage of mucin caused by inadvertent rupture of the lesion during operation, which may lead to pseudomyxoma peritonei if the lesion is neoplastic [24]. However, laparoscopic dissection, grasping of the appendix specimen, pneumoperitoneum, or transport of the specimen through the abdominal wall might contribute to peritoneal dissemination of a tumor, if present. These setbacks can be avoided by taking precautions like using bowel holding graspers (non-traumatic) to handle the mucocele, and using a nonpermeable bag to deliver the specimen out of the port [25]. Conversion to laparotomy should be done if the mucocele ruptures. Preoperative recognition of patients at particularly high risk for AM may be useful for several reasons, including appropriate provision of informed consent, timing of surgery; access to higher levels of care before and/or after surgery, and to avoid unintended rupture and the development of pseudomyxoma peritonei during laparoscopic surgery. As a retrospective study our data clearly have important limitations. The retrospective design of this study


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prohibited the development of a standardized protocol for patient evaluation and our database is limited to the variables that were collected for distinguishing AM from acute appendicitis. Some important information was not recorded, i.e., six (26 %) out of 23 patients were not tested for hematuria. Another important limitation of our study was that the CT findings for study patients were not examined because most patients and controls did not undergo CT examination. In conclusion, we developed a simple scoring system using routinely collected radiologic and laboratory parameters to predict the occurrence of AM. If not routinely performed, we suggest doing urinalysis in all patients who have an appendix with outer diameter [10 mm. Validation studies of this new scoring system are needed to support its use in routine clinical practice.

10. Kessler N, Cyteval C, Gallix B, Lesnik A, Blayac PM, Pujol J, Bruel JM, Taourel P. Appendicitis: evaluation of sensitivity, specificity, and predictive values of US, Doppler US, and laboratory findings. Radiology. 2004;230:472–8. 11. Lien WC, Huang SP, Chi CL, Liu KL, Lin MT, Lai TI, Liu YP, Wang HP. Appendiceal outer diameter as an indicator for differentiating appendiceal mucocele from appendicitis. Am J Emerg Med. 2006;24:801–5. 12. Mariadason JG, Wang WN, Wallack MK, Belmonte A, Matari H. Negative appendicectomy rate as a quality metric in the management of appendicitis: impact of computed tomography, Alvarado score and the definition of negative appendicectomy. Ann R Coll Surg Engl. 2012;94:395–401. 13. Yamamoto M, Ando T, Kanai S, Natsume H, Miyake K, Mitsuya H. Abnormal urinalysis in acute appendicitis. Acta Urol Jpn. 1985;31:1723–4. 14. Mohr DN, Offord KP, Owen RA, Melton LJ III. Asymptomatic microhematuria and urologic disease. A population-based study. JAMA. 1986;256:224–9. 15. Baskin LS, Stoller ML. Unusual appendiceal pathology presenting as urologic disease. Urology. 1991;38:432–6. 16. Parada R, Rosales A, Algaba F, Lluis F, Villavicencio H. Mucocele of the appendix: an unusual cause of obstructive kidney failure. Br J Urol. 1998;82:444–5. 17. Arisawa C, Takeuchi S, Wakui M. Appendiceal carcinoma invading the urinary bladder. Int J Urol. 2001;8:196–8. 18. Parsons JK, Freeswick PD, Jarrett TW. Appendiceal cystadenoma mimicking a cystic renal mass. Urology. 2004;63:981–2. 19. Oliphant UJ, Rosenthal A. Hematuria: an unusual presentation for mucocele of the appendix. Case report and review of the literature. JSLS. 1999;3:71–4. 20. Vale J, Kirby RS. Haematuria due to mucocele of the appendix. Br J Urol. 1989;63:218–9. 21. Ng KC, Tan CK, Lai SW, Chen DR, Chen WK. Mucocele of the appendix with hematuria. Yale J Biol Med. 2001;74:9–12. 22. Andersson RE. Meta-analysis of the clinical and laboratory diagnosis of appendicitis. Br J Surg. 2004;91:28–37. 23. Yakan S, Caliskan C, Uguz A, Korkut MA, Coker A. A retrospective study on mucocele of the appendix presented with acute abdomen or acute appendicitis. Hong Kong J Emerg Med. 2011;18:144–9. 24. Park KB, Park JS, Choi GS, Kim HJ, Park SY, Ryuk JP, Choi WH, Jang YS. Single-incision laparoscopic surgery for appendiceal mucoceles: safety and feasibility in a series of 16 consecutive cases. J Korean Soc Coloproctol. 2011;27:287–92. 25. Rangarajan M, Palanivelu C, Kavalakat A, Parthasarathi R. Laparoscopic appendectomy for mucocele of the appendix: report of 8 cases. Indian J Gastroenterol. 2006;25:256–7.

Conflict of interest

The authors declare no conflict of interest.

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