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Year : 2013  |  Volume : 2  |  Issue : 4  |  Page : 286-289

Mucocele appendix: A rare differential diagnosis of pelvic mass

1 Department of Surgery, MGM Medical College and Hospital, Navi Mumbai, Maharashtra, India
2 Department of Obstetrics & Gynecology, MGM Medical College and Hospital, Navi Mumbai, Maharashtra, India
3 Department of Urology, MGM Medical College and Hospital, Navi Mumbai, Maharashtra, India

Date of Web Publication7-Feb-2014

Correspondence Address:
Vishal Yadav
Department of Surgery, MGM Medical College and Hospital, Navi Mumbai - 410 206, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2278-344X.126764

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Mucocele of the appendix is a descriptive term that implies a dilated appendiceal lumen caused by abnormal accumulation of mucus. Mucocele is found in 0.2-0.3% of all appendectomy specimens. The male to female ratio is 1:4 and the average age at the time of diagnosis is over 50 years. Ultrasonography and computed tomography are useful tools for the diagnosis of appendiceal mucocele. Pre-operative diagnosis is a major component for minimizing intra operative and post-operative complications. We herein report a case of 40-year-old female presented as pelvic mass and this pose a diagnostic challenge

Keywords: Appendectomy, appendix, mucinous cystadenoma, mucocele

How to cite this article:
Yadav V, Borse R, Joseph S, Bansal P. Mucocele appendix: A rare differential diagnosis of pelvic mass. Int J Health Allied Sci 2013;2:286-9

How to cite this URL:
Yadav V, Borse R, Joseph S, Bansal P. Mucocele appendix: A rare differential diagnosis of pelvic mass. Int J Health Allied Sci [serial online] 2013 [cited 2023 Nov 30];2:286-9. Available from: https://www.ijhas.in/text.asp?2013/2/4/286/126764

  Introduction Top

Appendiceal mucocele is a rare entity that can present with a variety of clinical symptoms or occur as an incidental surgical finding. The incidence is 0.2-0.4% of all appendectomized specimens. [1],[2],[3] Appendiceal mucocele is a progressive dilatation of the appendix from the intraluminal accumulation of the mucoid substance. [3],[4] It may be a benign or malignant process. There are four histological types, which lead to individualized surgical treatment and course in each case. [3] Pre-operative diagnosis that distinguishes Appendiceal mucocele from acute appendicitis is essential for the best choice of surgical approach (open vs. laparoscopic) to prevent peritoneal dissemination and perform the appropriate surgery. [3],[5] In our case, mucocele of appendix presented as pelvic mass which is a rare presentation and misleads the clinician.

  Case Report Top

This was a case report of a 40-year-old female patient who presented to surgery out-patient department with the complaints of the right sided abdominal pain and discomfort, altered bowel habits and lump in the abdomen since 5 months. Patient was asymptomatic 5 months back when she developed vague pain in the lower abdomen. Since last 2 months patient noticed a lump in right iliac fossa, which was gradually increasing in size associated with altered bowel habits. There were no associated urinary or menstrual complaints. On examination, patient was afebrile had pulse rate of 80 beats/min and blood pressure of 130/80 mmHg. Abdominal examination revealed a relatively fixed and smooth lump in the right iliac fossa. On per-abdomen examination, there was palpable lump of about 15 cm Χ 10 cm with limited mobility, smooth surface and non-tender with no local rise of temperature. Rest of the abdominal and systemic examination was unremarkable. Laboratory investigations, including tumor markers cancer antigen (CA)-19-9, carcinoembryonic antigen and CA-125 were within the normal limits. Ultrasonography (USG) of the abdomen showed a heterogenic mass (95 mm Χ 70 mm Χ 32 mm in dimensions) involving ileocecal part of the intestines extending in pelvis. Computed tomography (CT) imaging revealed a soft-tissue mass measuring 12 cm Χ 8 cm with peripheral enhancement in the region of the cecum [Figure 1]. The patient underwent colonoscopy, which revealed a sub-mucosal protrusion to the lumen of the cecum, in the region of the appendiceal orifice. Diagnostic laparoscopy was performed, which revealed that the cystic mass involving appendix [Figure 2]. Conversion to open surgery was done due to difficulty in dissection of the lump from the cecum. Surgical exploration revealed the mass to be an appendix mucocele. Simple appendectomy was performed. Frozen section examination revealed benign mucoid lesion. Formal pathologic report was hyperplastic type mucocele with evidence of secondary changes and chronic inflammatory mucosa of the intestine [Figure 3]. The mucocele was 11 cm Χ 7 cm Χ 4 cm in dimensions with a wall thickness of 2 mm. There was no evidence of malignancy. Post-operative course was unremarkable and she was discharged home on the 5 th post-operative day.
Figure 1: Computed tomography abdomen showing a soft tissue mass measuring 12 cm × 8 cm with peripheral enhancement in the region of the cecum

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Figure 2: Diagnostic laproscopy was done, which revealed that the cystic mass involving appendix

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Figure 3: Histo-pathologic report was hyperplastic type mucocele with evidence of secondary changes and chronic inflammatory mucosa of the intestine

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  Disscusion Top

Mucocele of the appendix is a descriptive term for an appendix distention by mucous secondary to occlusion of lumen. Mucocele of the appendix was first described by Rokitansky (1842) and was formally named by Feren (1876). Since that time, there has been some debate as to the gross diagnosis of mucocele. Some consider the term to encompass a large group of conditions involving the appendix, pancreas, or ovaries, with diverse morphological features and pathogenesis. These conditions share the common feature of obstructive process or hyperplasia of mucinous epithelium or both leading to gross mucinous accumulation. Others consider mucocele to be a strictly neoplastic process that can spread to lymph nodes, extend into surrounding tissue or seed the peritoneum. [6] The latter description encompasses most mucocele-related diagnoses and thus, right hemicolectomy is an appropriate first step in managing suspicious mucinous collections of the appendix. Mucocele of the appendix is a descriptive term for an appendix distended by mucus, secondary to mucinous cystadenoma (63%), mucosal hyperplasia (25%), mucinous cystadenocarcinoma (11%) and retention cyst. [6] Mucocele can also occur due to occlusion of the lumen by endometriosis or carcinoid tumor. Overall, appendiceal mucocele makes up about 0.2-0.3% of appendix specimen. The male to female ratio is 1:4 and the average age at the time of diagnosis is over 50 years. [1],[3] Approximately, 23-50% of patients are asymptomatic. [7] Clinical manifestations of appendiceal mucoceles are non-specific, thus diminishing the rate of accurate pre-operative diagnosis. These include abdominal pain, palpable mass, weight loss, nausea and vomiting, change in bowel habits, appendicitis or lower gastrointestinal bleeding. One-quarter of mucoceles are asymptomatic. However, when symptoms are present a cystadenocarcinoma is more likely to be encountered. In general, only one-third of them are malignant, whereas the risk of malignancy increases with size. These data may be influenced by the fact that routine incidental appendectomy is generally performed during gynecological or other surgical procedures, increasing the rate of incidental benign appendiceal mucocele. [1],[3],[8],[9],[10] The incidence of neoplasm of colon, rectum, ovarian, bladder and gastrointestinal track tumors is reported in patients with appendiceal mucocele and patient to be under surveillance for the rest of life.

They are pathologically divided into four categories:

1. Simple or retention mucoceles resulting from obstruction of the appendiceal outflow, usually by a fecalith and characterized by normal epithelium and mild luminal dilatation up to 1 cm

2. Mucoceles with hyperplastic epithelium where luminal dilatation is also mild; these constitute 5-25% of mucoceles

3. Benign mucoceles, the most common form, accounting for 63-84% of cases. These exhibit mostly epithelial villous adenomatous changes with some degree of epithelial atypia and are characterized by marked distention of the lumen up to 6 cm. Our patient belongs to this group

4. Malignant mucinous cystadenocarcinomas, representing 11-20% of cases. They are distinguished from the previous group by their glandular stromal invasion and/or presence of epithelial cells in the peritoneal implants. The luminal distention is usually severe. [3],[7]

The initial detection of the lesion may be facilitated by radiological, sonographic or endoscopic means. On barium enema, there is usually non filling or partial filling of the appendix with contrast. The lesion may be seen as a sharply outlined sub mucosal or extrinsic mass indenting the caecum and laterally displacing it. [11] Ultrasound is the first line diagnostic modality for patients with abdominal lump. USG findings can be variable. Purely cystic lesions with anechoic fluid, hypoechoic masses with fine internal echoes as well as complex hyperechoic masses can be seen depending on the contents. The onion skin sign is considered to be specific for mucocele of the appendix. [12] Different sonographic findings of Appendiceal mucocele and acute appendicitis have been described. Appendix diameter 15 mm or more in USG examination has been determined as the threshold for Appendiceal mucocele diagnosis with a sensitivity of 83% and specificity of 92%. [3] Outer diameter threshold for acute appendicitis diagnosis has been established as 6 mm. USG examinations revealed a cystic mass in the right lower quadrant our patients. These findings revealed suspicion of Appendiceal mucocele. Colonoscopic findings include the "volcano sign," the appendiceal orifice seen in the centre of a firm mound covered by normal mucosa or a yellowish, lipoma-like submucosal mass. A yellowish mucous discharge would be visible from appendiceal orifice during colonoscopy. [13] CT of the abdomen usually shows a cystic well-encapsulated mass sometimes with mural calcification, in the expected location of the appendix. It may be causing extrinsic pressure on the cecal wall without any surrounding inflammatory reaction. [3],[11] Differential diagnosis includes carcinoid, lymphoma, mesenteric cysts, ovarian masses and malignant neoplasms of the appendix.

Simple appendectomy is the choice of surgical treatment for patients with benign mucocele that has negative margins of resection without perforation. No long-term follow-up is needed for these patients. [2],[9],[14] For patients with perforated mucocele, with positive margins of resection, positive cytology and positive appendiceal lymph nodes, right colectomy/cytoreductive surgery/heated intraperitoneal chemotherapy and early post-operative intraperitoneal chemotherapy should be performed. Long-term follow-up is obligatory for these patients. [5],[14] Surgical complications of Appendiceal mucocele include intestinal obstruction, intussusceptions, intestinal bleeding, fistula formation and volvulus. The worst complication is pseudomyxoma peritonei, characterized by peritoneal dissemination caused by iatrogenic or spontaneous rupture of the mucocele. [5] The tissues should be handled carefully during surgery in order to avoid rupture of the mucocele. Laparoscopic approach has an increased risk of rupture and subsequent pseudomyxoma peritonei formation. [2],[5],[9] In benign mucocele, the pseudomyxoma is confined to the peri-appendicular area. In malignant cases, this dissemination is considered a real metastatic entity; retro-peritoneal or pleural implants are occasionally reported. Moreno et al. [5] in their study suggest conversion to an open appendectomy in case of mucocele when laparoscopic appendectomy is intended. [10] Laparoscopic approach has been adopted for a small number of patients. At the time of surgery, a spontaneous appendiceal perforation or any mucus extravasation from the appendiceal lumen is strongly suggestive of an underlying malignancy and should perform right hemicolectomy. If the lesion is confined to the appendix, has no surrounding infiltration and is followed by negative frozen-section examination and clear margins of resection, wide local resection is usually adequate. Conversion to laparotomy should be considered if the lesion is traumatically grasped or if the tumor clearly extends beyond the appendix or if there is evidence of malignancy such as peritoneal deposits. An appendectomy is advised for focal or diffuse mucosal hyperplasia and cystadenoma when appendiceal base is intact. Cecal resection for cystadenoma and right hemicolectomy for cystadenocarcinoma.

Appendiceal mucoceles are rare and are often found incidentally. Incorrect intraoperative handling may lead to major complications. Suggestive and characteristic imaging findings can help establish the pre-operative diagnosis of mucocele, highlighting the role radiologists play in pre-operative planning and in ensuring good patient outcome. Pre-operative recognition of mucocele of the appendix is important due to the possibility of rupture at surgery with development of pseudomyxoma peritonei and to predict malignant transformation.

In our case, mucocele of appendix presented as pelvic mass, which is a rare presentation and misleads the clinician. Mucocele of appendix can mimic an adnexal mass and prove to be diagnostic challenge. In women presenting with right iliac fossa mass, an appendiceal pathology should be considered in the differential diagnosis.

  References Top

1.Pitiakoudis M, Tsaroucha AK, Mimidis K, Polychronidis A, Minopoulos G, Simopoulos C. Mucocele of the appendix: A report of five cases. Tech Coloproctol 2004;8:109-12.  Back to cited text no. 1
2.Zanati SA, Martin JA, Baker JP, Streutker CJ, Marcon NE. Colonoscopic diagnosis of mucocele of the appendix. Gastrointest Endosc 2005;62:452-6.  Back to cited text no. 2
3.Lien WC, Huang SP, Chi CL, Liu KL, Lin MT, Lai TI, et al. Appendiceal outer diameter as an indicator for differentiating appendiceal mucocele from appendicitis. Am J Emerg Med 2006;24:801-5.  Back to cited text no. 3
4.Jaffe BM, Berger DH. The appendix. In: Brunicardi FC, Andersen DK, Billiar TR, Dunn DL, Hunter JG, Pollock RE editors. Schwartz′s Principles of Surgery. International ed. 9 : McGraw Hill Companies Inc.; 2005. p. 1119-37.  Back to cited text no. 4
5.González Moreno S, Shmookler BM, Sugarbaker PH. Appendiceal mucocele. Contraindication to laparoscopic appendectomy. Surg Endosc 1998;12:1177-9.  Back to cited text no. 5
6.Higa E, Rosai J, Pizzimbono CA, Wise L. Mucosal hyperplasia, mucinous cystadenoma, and mucinous cystadenocarcinoma of the appendix. A re-evaluation of appendiceal "mucocele". Cancer 1973;32:1525-41.  Back to cited text no. 6
7.Bartlett C, Manoharan M, Jackson A. Mucocele of the appendix-A diagnostic dilemma: A case report. J Med Case Rep 2007;1:183.  Back to cited text no. 7
8.Ruiz-Tovar J, Teruel DG, Castiñeiras VM, Dehesa AS, Quindós PL, Molina M. Mucocele of the appendix. World J Surg 2007;31:542-8.  Back to cited text no. 8
9.Rampone B, Roviello F, Marrelli D, Pinto E. Giant appendiceal mucocele: Report of a case and brief review. World J Gastroenterol 2005;11:4761-3.  Back to cited text no. 9
10.Lau H, Yuen WK, Loong F, Lee F. Laparoscopic resection of an appendiceal mucocele. Surg Laparosc Endosc Percutan Tech 2002;12:367-70.  Back to cited text no. 10
11.Dachman AH, Lichtenstein JE, Friedman AC. Mucocele of the appendix and pseudomyxoma peritonei. AJR Am J Roentgenol 1985;144:923-9.  Back to cited text no. 11
12.Skaane P, Ruud TE, Haffner J. Ultrasonographic features of mucocele of the appendix. J Clin Ultrasound 1988;16:584-7.  Back to cited text no. 12
13.Hamilton DL, Stormont JM. The volcano sign of appendiceal mucocele. Gastrointest Endosc 1989;35:453-6.  Back to cited text no. 13
14.Dhage-Ivatury S, Sugarbaker PH. Update on the surgical approach to mucocele of the appendix. J Am Coll Surg 2006;202:680-4.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3]

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