Indian Journal of Radiology and Imaging Indian Journal of Radiology and Imaging

QUIZ
Year
: 2001  |  Volume : 11  |  Issue : 3  |  Page : 147--148

Radiological quiz - abdominal


NBS Mani, Bimal P Sood, Sudha Suri 
 Dept of Radiodiagnosis and Imaging, PGIMER, Chandigarh - 160 012, India

Correspondence Address:
Bimal P Sood
Dept of Radiodiagnosis and Imaging, PGIMER, Chandigarh - 160 012
India




How to cite this article:
Mani N, Sood BP, Suri S. Radiological quiz - abdominal.Indian J Radiol Imaging 2001;11:147-148


How to cite this URL:
Mani N, Sood BP, Suri S. Radiological quiz - abdominal. Indian J Radiol Imaging [serial online] 2001 [cited 2020 Feb 19 ];11:147-148
Available from: http://www.ijri.org/text.asp?2001/11/3/147/30561


Full Text

A seventy-eight-years-old woman presented with a six-months history of heaviness in the lower abdomen associated with nausea and occasional vomiting. There was no history of abdominal pain, distension, weight loss or loss of appetite. Clinical examination showed our patient to be a moderately built, well-nourished elderly woman with a vague, non-tender, slightly mobile mass in the right iliac fossa. This mass did not move appreciably with respiration. Laboratory examination revealed normal hemoglobin, WBC and electrolyte counts. Ultrasound examination revealed a large oblong well-defined cystic lesion in the right iliac fossa with heterogeneous echoes within the lumen. There was no free fluid. We performed a barium enema examination and a contrast-enhanced CT scan. A barium examination and CT were performed [Figure 1],[Figure 2]. What is the diagnosis?

 View Answer

 Radiological Diagnosis



 MUCOCELE OF THE APPENDIX DUE TO MUCINOUS CYSTADENOCARCINOMA

.

Mucocele of appendix is a descriptive term that implies an appendix distended by abnormal accumulation of mucus within its lumen. It is a rare entity with a reported incidence of 0.2-0.3% [1] in appendectomy specimens. The ratio of incidence in women to men is 4:1and the average age of presentation is above 55 years [2].

Currently mucoceles of the appendix can be divided into three categories:

Retention mucocele with normal / hyperplastic appendiceal mucosa Mucinous cystadenoma with neoplastic epithelium similar to that seen in villous adenomas and adenomatous polyps and Mucinous cystadenocarcinoma with neoplastic epithelium similar to that seen in adenocarcinoma of colon [3].

Rupture of a mucocele may result in pseudomyxoma peritonei, which is characterized by implants of mucinous epithelium on the peritoneal surfaces and mucus accumulation within the peritoneal cavity. This leads to adhesions and intestinal obstruction. Accurate preoperative diagnosis of mucocele of appendix is extremely helpful to the surgeon in that it may reduce the possibility of rupture and contamination by the mucocele contents during mobilization and resection [3].

The typical imaging findings of an appendiceal mucocele are a cystic mass in the expected region of the appendix. Plain abdominal radiographs may show mass effect on the adjacent bowel or bladder. Sometimes a curvilinear calcification may be seen in the right lower quadrant. Barium enema examination may show an extrinsic impression on the cecum [Figure 1], terminal ileum or sigmoid colon. The classical appearance is a "vertical fold" pattern representing a concentric ring appearance of cecal mucosal folds directed towards the obstructed appendiceal orifice [4]. With the advent of advanced imaging techniques like sonography and CT scan, correct diagnosis of mucocele of appendix is possible [5].

Ultrasound examination usually reveals an oblong heterogeneous cystic mass. The degree of internal echogenicity is related to the number of acoustic interfaces provided by mucin. Excellent through transmission and posterior enhancement are usually the rule in this condition. The mass lesion is well-encapsulated unless rupture has occurred. CT scan reveals a low attenuation, well-encapsulated mass with smooth regular walls and displacement of bowel loops. It is important to note that there is no periappendiceal inflammation or abscess, which accompanies acute appendicitis. Though there are no unique imaging characteristics to distinguish between the three groups of mucocele, the cystadenomas and cystadenocarcinomas are usually larger than the retention mucoceles and spread to the peritoneal surfaces more readily. The presence of enhancing mural nodule in the wall of the mucocele in CT [Figure 2] suggests mucinous cystadenocarcinoma [5]. Our patient was operated upon and the histopathology of the mass lesion revealed mucinous cystadenocarcinoma of the appendix.

References

1Dachman A, Lichenstein J, Friedman A. Mucocele of appendix and pseudomyxoma peritonei. AJR 1985; 144: 924-929.
2Aho AJ, Heinonen R, Lauren P. Benign and malignant mucocele of the appendix. Acta Chir Scand 1973; 139: 392-400.
3Higa E, Rosai J, Pizzimbono, CA et al . Mucosal hyperplasia, mucinous cystadenoma and mucinous cystadenocarcinoma of the appendix: A reevaluation of appendiceal mucocele. Cancer 1973; 32: 1525-1541.
4Madwed D, Mindelzun R, Jeffrey RB. Mucocele of the appendix: imaging findings. AJR 1992; 169: 69-72.
5Kim SH, Lim HK, Lee WJ, Lim JH, Byun JY. Mucocele of thew appendix: ultrasonographic and CT Findings. Abdom Imaging 1998; 23: 292-296.