- Case report
- Open Access
- Open Peer Review
Cystadenocarcinoma of the appendix: an incidental imaging finding in a patient with adenocarcinomas of the ascending and the sigmoid colon
https://doi.org/10.1186/1471-230X-3-30
© Pitiakoudis et al; licensee BioMed Central Ltd. 2003
- Received: 28 July 2003
- Accepted: 22 October 2003
- Published: 22 October 2003
Abstract
Background
Primary adenocarcinomas of the appendix are uncommon. Mucoceles that result from mucinous adenocarcinomas of the appendix may be incidentally detected on imaging.
Case presentation
A case of a mucocele of the appendix, due to cystadenocarcinoma, is presented as an incidental imaging finding in a female, 86-year-old patient. The patient was admitted due to rectal hemorrhage and underwent colonoscopy, x-ray, US and CT. Adenocarcinoma of the ascending colon, adenomatous polyp of the sigmoid colon and a cystic lesion in the right iliac fossa were diagnosed. The cystic lesion was characterized as mucocele. The patient underwent right hemicolectomy, excision of the mucocele and sigmoidectomy. She recovered well and in two-year follow-up is free from cancer.
Conclusions
Preoperative diagnosis of an underlying malignancy in a mucocele is important for patient management, but it is difficult on imaging studies. Small lymph nodes or soft tissue stranding in the surrounding fat on computed tomography examination may suggest the possibility of malignancy.
Keywords
- Mucocele of the appendix
- Adenocarcinoma of the colon
- Ultrasonography
- Computed Tomography
Background
Primary adenocarcinoma of the appendix is uncommon [1]. On gross examination this tumor may be presented as mucocele. Although there are many pathology reports of primary cystadenocarcinoma of the appendix, only a limited number of cases have appeared in the radiology or surgical literature [2–6]. Preoperative diagnosis is difficult but important for surgical management. We present a case of primary cystadenocarcinoma of the appendix occurring concurrently with adenocarcinoma of the colon.
Case report
Plain film of the abdomen, revealing a soft tissue density lesion with peripheral calcification (arrows). A mucocele of the appendix or an echinococcus cyst may have a similar appearance.
Transverse ultrasonogram of the right iliac fossa. The mucocele is shown as a cystic lesion. Internal echoes in the middle of the cyst are not usually seen in a simple mucocele.
Axial CT section through the right lower abdomen. A cystic lesion with both curvilinear and nodular calcification in the wall is demonstrated (arrows).
Axial CT section obtained 1 cm more cephalic to Figure 1. Two small nodules close to the posterolateral wall of the lesion are demonstrated (arrows). Soft tissue strands are present in the fatty tissue around the mucocele (arrows).
Axial CT section through ascending colon. A large tumor is demonstrated (arrows).
Malignant mucocele and adenocarcinoma of the ascending colon.
Malignant mucocele, adenocarcinoma of the ascending colon and adenocarcinoma of the sigmoid colon.
Discussion
Mucocele of the appendix is a descriptive term for mucinous distension of the appendiceal lumen, regardless of the underlying pathology. The incidence of mucocele in appendectomy specimens is about 0.25% [7]. The male to female ratio is 1:4 with a mean age of 55 years at diagnosis [7]. The most common symptom is right lower abdominal pain mimicking appendicitis, although mucocele can also be asymptomatic, as in our patient, found incidentally on imaging [2, 6]. In our case the underlying pathology proved to be a mucinous cystadenocarcinoma of the appendix. Primary adenocarcinoma of the appendix is uncommon, occurring in 0.08% of all appendectomies [1]. Mucinous cystadenocarcinoma is usually a well-differentiated neoplasm, and the gross morphology of this tumor is that of a mucocele [2]. Although there are many pathology reports of primary mucinous cystadenocarcinoma, only a few cases have been reported in the radiology literature [2–5]. Preoperative diagnosis, although important for proper surgical management, is difficult due to the absence of specific imaging findings. The presence of a cystic mass in the expected area of the appendix with enhancing wall and nodularity on CT examination suggests the possibility of mucinous cystadenocarcinoma [2–4, 8]. Wall thickness has not been proven to be a reliable differential point between neoplastic and non-neoplastic causes of mucocele of the appendix [3], thus the presence of relatively thin wall in our case can not exclude malignancy. Curvilinear nodular or punctuate wall calcifications, as in our case, have been reported in both malignant and benign mucoceles [2, 3].
In our case, the two very small nodules present close to the wall of the mucocele were consistent with lymph nodes. This finding along with minimal stranding in the surrounding fat may be suggestive of a malignant lesion and should be carefully evaluated as an aid in the differential diagnosis. The cystadenocarcinoma of the appendix was associated with an adenocarcinoma of the ascending colon and an adenomatous polyp with malignant transformation of the sigmoid colon. There have been reports of other tumors associated with adenomatous change in the appendix, including the gastrointestinal tract, ovary, breast and kidney [6]. However, the most common association was with adenocarcinoma of the colon. Indeed, 21.4% of a series of appendiceal adenomas were associated with colon neoplasia [6]. A common underlying cause is suggested, since the histological features of appendiceal adenocarcinomas are identical to those of adenocarcinomas elsewhere in the large bowel [6]. Considering that the appendix is a part of the large intestine, adenomatous polyps, papillary adenomas and adenocarcinomas in the appendix are simply an expression of colonic neoplasms in this particular anatomic location. Thus, low incidence of mucoceles is attributed to the relatively small size of the appendix in comparison to the rest of the large bowel [6].
Mucoceles are often an incidental finding on imaging examination of the abdomen. Small lymph nodes or stranding in the surrounding fat on CT may arise the possibility of a malignant underlying lesion. In these cases a thorough search for other colonic neoplasms is essential.
Declarations
Acknowledgements
We thank the patient for giving us written consent for publishing this study.
Authors’ Affiliations
References
- Collins DC: A study of 50,000 specimens of the human vermiform appendix. Surg Gynecol Obstet. 1955, 101: 435-437.Google Scholar
- Lim HK, Lee WJ, Kim SH, Kim B, Cho JM, Byun JY: Primary mucinous cystadenocarcinoma of the appendix: CT findings. AJR. 1999, 173: 1071-1074.View ArticlePubMedGoogle Scholar
- Kim SH, Lim HK, Lee WJ, Lim JH, Byun JY: Mucocele of the appendix: Ultrasonographic and CT findings. Abdominal Imaging. 1998, 23: 292-296. 10.1007/s002619900343.View ArticlePubMedGoogle Scholar
- Madwed D, Mindelzum R, Jeffrey RB: Mucocele of the appendix: Imaging findings. AJR. 1992, 159: 69-72.View ArticlePubMedGoogle Scholar
- Dachman AH, Lichtenstein JE, Friedman AC: Mucocele of the appendix and pseudomyxoma peritonei. AJR. 1985, 144: 923-929.View ArticlePubMedGoogle Scholar
- Wolff M, Ahmed N: Epithelial neoplasms of the vermiform appendix (exclusive of carcinoid): II. Cystadenomas, papillary adenomas, and polyps of the appendix. Cancer. 1976, 37: 2511-2522.View ArticlePubMedGoogle Scholar
- Aho AJ, Heinonen R, Lauren P: Benign and malignant mucocele of the appendix. Acta Chir Scand. 1973, 139: 392-400.PubMedGoogle Scholar
- Pickhardt PF, Levy AD, Rohrmann CA, Kende AI: Primary neoplasms of the appendix: Radiologic spectrum of disease with pathologic correlation. RadioGraphics. 2003, 23: 645-662.View ArticlePubMedGoogle Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-230X/3/30/prepub
Pre-publication history
Copyright
This article is published under license to BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.