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Background

This is a rare carcinoma. It's importance lies in the treatment considerations as well as its association with conditions such as pseudomyxoma peritonei.

OUTLINE

Epidemiology  
Disease Associations  
Pathogenesis  
Gross Appearance and Clinical Variants  
Histopathological Features and Variants  
Differential Diagnosis  
Prognosis and Treatment  
Commonly Used Terms  
Internet Links  


EPIDEMIOLOGY CHARACTERIZATION
SYNONYMS  


Appendiceal tumors: retrospective clinicopathologic analysis of appendiceal tumors from 7,970 appendectomies.

Connor SJ, Hanna GB, Frizelle FA.

Department of Surgery, Christchurch Hospital, New Zealand.

Dis Colon Rectum 1998 Jan;41(1):75-80 Abstract quote

BACKGROUND: Appendiceal tumors are rare and often unexpectedly discovered in an acute situation, in which decision-making is difficult. To help define the most appropriate management, a retrospective analysis was undertaken to describe the clinicopathologic behavior of appendiceal tumors, and the literature was reviewed of the management of the different types of appendiceal tumors.

METHOD: From a single center, a histopathologic database of 7,970 appendectomies, all appendiceal tumors, were identified and case notes reviewed. Analysis of clinical presentation, histopathology, operation, and outcome is presented.

RESULTS: During a 16-year period (7,970 appendectomies), 74 patients (0.9 percent) with appendiceal tumors were identified: 42 carcinoid, 12 benign, and 20 malignant. Acute appendicitis was the most common presentation (49 percent), and 9.5 percent were incidental findings. Primary malignant tumors of the appendix were found in 0.1 percent of all appendectomies. Secondary malignant disease was identified in the appendix of 11 patients, most commonly (55 percent) from patients with primary colorectal disease. There was a high incidence of synchronous and metachronous colorectal cancer in all appendiceal tumors: carcinoids, 10 percent; benign tumors, 33 percent; secondary malignancies, 55 percent; primary malignancies, 89 percent.

CONCLUSION: Appendiceal tumors are uncommon and most often present as appendicitis. Most are benign and can be managed by appendectomy, except adenocarcinomas and carcinoids larger than 2 cm, which are most appropriately managed by right hemicolectomy. A suggested management algorithm is provided. Controversy exists over the management of carcinoids 1 to 2 cm in size and adenocarcinoids. All types of appendiceal tumors have a high incidence of synchronous and metachronous colorectal cancer.


Adenocarcinoma of the vermiform appendix. A population study.

Nielsen GP, Isaksson HJ, Finnbogason H, Gunnlaugsson GH.

Department of Pathology, University of Iceland, Reykjavik.

APMIS 1991 Jul;99(7):653-6 Abstract quote

We report seven cases of adenocarcinoma of the vermiform appendix occurring in Iceland during 1974-1989.

The patients ranged in age from 25-83 years, mean age 55.1 years. There were five males and two females. Five had mucinous adenocarcinoma, two had adenocarcinoma. Four patients presented with symptoms and signs of acute appendicitis and all had surgically resectable disease. Three of these patients were alive with no evidence of disease four months, two years and 15 years after presentation; one death of disease occurred seven years after ileocecal resection. In three cases, the clinical presentation was that of metastatic adenocarcinoma of unknown origin. Of these patients two were diagnosed at autopsy and one after appendectomy for perforated appendicitis. Survival in this group was six weeks, three months and twelve months, respectively. In none of our patients was the diagnosis made preoperatively and no tumors were found in appendices removed incidental to other intra-abdominal operations.

The incidence of adenocarcinoma of the vermiform appendix in Iceland during 1974-1989 was approximately 0.2 cases/100.000/year.

 

DISEASE ASSOCIATIONS CHARACTERIZATION
PSEUDOMYXOMA PERITONEI  

 

PATHOGENESIS CHARACTERIZATION
GENERAL  


Epithelial Neoplasms of the Appendix and Colorectum.

Carr NJ, Emory TS, Sobin LH.

Department of Cellular Pathology, Southampton University Hospitals National Health Service Trust, Southampton, Hampshire, England (Dr Carr), and Department of Hepatic and Gastrointestinal Pathology, Armed Forces Institute of Pathology, Washington, DC (Drs Emory and Sobin).

Arch Pathol Lab Med 2002 Jul;126(7):837-841 Abstract quote

Context.-Carcinomas of the appendix are usually well-differentiated mucinous adenocarcinomas that tend to produce pseudomyxoma peritonei and do not show metastatic spread until late in the disease process. In contrast, adenocarcinomas of the colon and rectum rarely result in pseudomyxoma peritonei and frequently metastasize, even if mucinous and well differentiated. These differences in behavior may be reflected by differences at the molecular level.

Objectives.-To examine adenocarcinomas and their precursor lesions (adenomas) of the appendix and colorectum and to determine whether differences exist in the numbers of proliferating and apoptotic cells or in expression of p53, bcl-2, and the standard form of CD44 (CD44s).

Design.-Retrospective analysis of surgical specimens.

Setting.-Multicenter study.

Patients.-Individuals treated surgically for tumors of the appendix or colorectum.

Interventions.-Sections were cut from formalin-fixed surgical specimens and immunohistochemical tests were performed for Ki-67 (as a marker of proliferating cells), M30 (as a marker of apoptotic cells), p53, CD44s, and bcl-2. Main Outcome Measures.-Expression of Ki-67, M30, p53, CD44s, and bcl-2 in tumor cells. Results.-The appendiceal adenomas showed significantly lower Ki-67 counts, p53 expression, and bcl-2 expression. When compared with adenocarcinomas of the colorectum in general (mucinous and nonmucinous), the appendiceal adenocarcinomas showed significantly lower Ki-67 counts, M30 counts, and CD44s expression. However, when the analysis was confined to well-differentiated mucinous adenocarcinomas, only the M30 count was significantly different.

Conclusions.-The lower proliferative and apoptotic activity of appendiceal carcinomas and the lower CD44s expression are in keeping with their more indolent behavior compared with adenocarcinomas of the colorectum. However, when only the subset of well-differentiated mucinous adenocarcinomas was compared, only the apoptotic activity was different, suggesting that the other differences were related to the morphologic structure of the lesions.

CHROMOSOMAL ABNORMALITIES  


Mucinous and nonmucinous appendiceal adenocarcinomas: different clinicopathological features but similar genetic alterations.

Kabbani W, Houlihan PS, Luthra R, Hamilton SR, Rashid A.

Department of Pathology, University of Texas M. D. Anderson Cancer Center, Houston, Texas.

 

Mod Pathol 2002 Jun;15(6):599-605 Abstract quote

The genetic alterations of appendiceal carcinomas have not been reported in detail.

We studied the clinicopathological factors and genetic alterations including microsatellite instability, p53 overexpression, and mutations of the K-ras proto-oncogene of 30 appendiceal adenocarcinomas, consisting of 23 mucinous and 7 nonmucinous carcinomas. Sixteen (70%) mucinous carcinomas presented with pseudomyxoma peritonei, but 6 of 7 (86%) nonmucinous carcinomas presented with appendicitis (P =.002). All carcinomas were microsatellite stable, and p53 overexpression was present in only 1 of 30 (3%) carcinomas. K-ras mutation was present in 11 of 20 (55%) carcinomas, including 8 of 16 (50%) mucinous and 3 of 4 (75%) nonmucinous carcinomas. The mean survival of patients with mucinous carcinomas was 26 +/- 19 months compared with 13 +/- 9 months for patients with nonmucinous carcinomas (P =.0002).

Our findings suggest that mucinous and nonmucinous carcinomas of appendix have similar genetic alterations, but different clinical presentation and prognosis.

GROSS APPEARANCE/
CLINICAL VARIANTS
CHARACTERIZATION
GENERAL  


Primary epithelial tumors of the appendix and a reappraisal of the appendiceal "mucocele".

Aranha GV, Reyes CV.

Dis Colon Rectum 1979 Oct;22(7):472-6 Abstract quote

A 28-year review of the records at Hines V.A. Medical Center revealed 17 primary epithelial tumors of the appendix. Five of these tumors were benign and 12 malignant. It is suggested that the term mucocele be abandoned, because it represents the end result rather than a definite pathologic entity.

The majority of benign tumors and carcinoid tumors of the appendix are discovered incidentally to other procedures. The majority of adenocarcinomas cause symptoms and signs of appendicitis. Simple appendectomy is sufficient treatment of all benign tumors of the appendix, and for all carcinoids that show no gross local metastases and are less than 2 cm in diameter. Simple appendectomy followed by right hemicolectomy or initial right hemicolectomy is the treatment of choice for all carcinoids of the appendix that show gross local metastases and are 2 cm or more in diameter and for all adenocarcinomas of the appendix, whether mucinous or colonic, in the absence of distant metastasis.

A new classification for primary epithelial tumors of the appendix is suggested.


Primary appendiceal adenocarcinoma.

Ozakyol AH, Saricam T, Kabukcuoglu S, Caga T, Erenoglu E.

Division of Gastroenterology, School of Medicine, Osmangazi University, Eskisehir, Turkey.

Am J Clin Oncol 1999 Oct;22(5):458-9 Abstract quote

Adenocarcinoma of the appendix is rarely encountered and is usually discovered at the pathology examination of the surgical specimen. Adenocarcinoma of the vermiform appendix is a rare neoplasm and constitutes <0.5% of all gastrointestinal neoplasms.

There is no symptom of appendiceal cancer, and it is very difficult to diagnose preoperatively. Most female patients are diagnosed as having a gynecologic disease. Second primary synchronous and metachronous neoplasms, especially in the gastrointestinal tract, are found in up to 35% of patients with appendix adenocarcinoma.

We report a case of adenocarcinoma in a 56-year-old woman misdiagnosed as having right ovarian carcinoma, and we review the literature.

VARIANTS  
OVARIAN METASTASIS  


The morphologic spectrum of ovarian metastases of appendiceal adenocarcinomas: a clinicopathologic and immunohistochemical analysis of tumors often misinterpreted as primary ovarian tumors or metastatic tumors from other gastrointestinal sites.

Ronnett BM, Kurman RJ, Shmookler BM, Sugarbaker PH, Young RH.

Department of Pathology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA

Am J Surg Pathol 1997 Oct;21(10):1144-55 Abstract quote

Twenty cases of ovarian metastases derived from appendiceal adenocarcinomas were analyzed.

The most common presentation was a pelvic mass. The appendiceal and ovarian tumors were diagnosed concurrently in 15 cases; in the remaining five, the ovarian tumors were diagnosed before the appendiceal tumor. The appendiceal adenocarcinomas demonstrated four morphologic patterns: 1) signet ring cell type, with or without glandular or goblet cell differentiation (14 cases); 2) mixed signet ring cell and intestinal type (two cases); 3) intestinal type (two cases); and 4) typical colorectal type (two cases).

The ovarian tumors were bilateral in 16 cases and were histologically similar to the associated appendiceal tumor in each case. Ovarian metastases that demonstrate signet ring cell, glandular, and goblet cell differentiation mimic metastases from gastric adenocarcinoma. Those that are derived from well-differentiated mucinous appendiceal adenocarcinomas mimic primary ovarian mucinous tumors and metastases from the pancreas and biliary tract. Metastases of appendiceal adenocarcinomas of colorectal type simulate both metastatic colorectal carcinoma and primary ovarian endometrioid carcinomas. The appendiceal and ovarian tumors were immunophenotypically identical in each case.

Approximately 50% of the appendiceal and ovarian tumors were positive for cytokeratin 7 (CK 7), and all were positive for cytokeratin 20 (CK 20). CK 20 positivity of the ovarian tumors is consistent with gastrointestinal origin; CK 7 positivity does not confirm ovarian origin, because appendiceal carcinomas are positive in 50% of cases. Metastatic appendiceal adenocarcinoma should be considered in the differential diagnosis of mucinous ovarian tumors with signet ring cell, goblet cell, or intestinal type differentiation, especially when these tumors are associated with extraovarian disease and are bilateral.

PEDIATRIC  

Adenocarcinoma of the appendix in a child.

Driver CP, Bowen J, Bruce J.

Department of Paediatric Surgery, Royal Manchester Children's Hospital, Pendlebury, England.

J Pediatr Surg 1998 Sep;33(9):1437-8 Abstract quote

Adenocarcinoma of the appendix is unusual at any age but occurs mostly in an elderly population.

The authors report a unique case presenting in a 10-year-old child and emphasize the importance of subjecting all resected specimens to histological examination.

 

HISTOLOGICAL TYPES CHARACTERIZATION
GENERAL  
MUCINOUS  
NON-MUCINOUS  
VARIANTS  

 

DIFFERENTIAL DIAGNOSIS KEY DIFFERENTIATING FEATURES
ADENOCARCINOID  


Adenocarcinoid (mucinous carcinoid) of the appendix.

Edmonds P, Merino MJ, LiVolsi VA, Duray PH.

Gastroenterology 1984 Feb;86(2):302-9 Abstract quote

Carcinoid tumors of the appendix are common incidental findings, but appendiceal tumors with histologic features of both carcinoids and adenocarcinomas are rare, and their biologic behavior is still unclear.

We studied 10 such cases among 45 appendiceal tumors seen at Yale-New Haven Hospital between 1960 and 1982. The patients, ranging in age from 23 to 65 yr, were all clinically symptomatic [acute appendicitis (5); abdominal mass (5)]. Right colectomy was performed in 5 patients; the other 5 underwent appendectomy only. In 1 case, metastasis to a lymph node was detected; 2 patients had ovarian metastases, and 4 patients had cecal invasion. One of the 10 patients died of widely disseminated tumor, 2 are living with persistent disease, and 5 remained free of disease from 1 to 5 yr after initial surgery. Two cases were lost to follow-up.

We conclude that the histology of these lesions is distinctive, enabling their differentiation from ordinary carcinoids. Because these lesions behave in a clinically more aggressive fashion than the usual appendiceal carcinoids, but are less virulent than adenocarcinoma, we support their classification as adenocarcinoids.

GOBLET CELL CARCINOID  


Goblet cell carcinoid tumor of the appendix. Report of five cases and review of the literature.

Chen V, Qizilbash AH.

Arch Pathol Lab Med 1979 Apr;103(4):180-2 Abstract quote

Five cases of goblet cell carcinoid tumor of the appendix showed characteristic histologic features that justified classification of these lesions as mucinous variants of carcinoid tumor. The tumor has low-grade malignancy, and metastases are uncommon.

Resemblance to mucinous adenocarcinoma of the appendix is striking, and the features that help to differentiate the two lesions are delineated.

METASTATIC ADENOCARCINOMA  

Acute appendicitis secondary to metastatic bronchogenic adenocarcinoma.

Gopez EV, Mourelatos Z, Rosato EF, Livolsi VA.

Department of Pathology and Laboratory Medicine, University of Pennsylvania Medical Center, Philadelphia 19104, USA.

Am Surg 1997 Sep;63(9):778-80 Abstract quote

Metastatic tumors to the appendix are not common. However, these tumors should be one of the differential diagnoses in patients with known primary malignancy, who present with signs and symptoms of acute appendicitis.

We report a case of an elderly male with poorly differentiated bronchogenic adenocarcinoma which metastasized to the appendix.

 

PROGNOSIS AND TREATMENT CHARACTERIZATION
PROGNOSTIC FACTORS  
GENERAL  


Primary adenocarcinoma of the appendix.

Delgado RR Jr, Mullen JT, Ehrlich FE.

South Med J 1975 Aug;68(8):976-8 Abstract quote

A case of primary adenocarcinoma of the appendix in which the patient had the usual symptoms of acute appendicitis is presented. A review of the literature showed the potential for early extension and nodal metastasis in this lesion and led to the recommendation of right hemicolectomy as the treatment of choice.

The operation should be done either primarily or secondarily after an appendectomy and should lead to a five-year survival of approximately 45%. Every effort should be made to make the diagnosis and provide definitive treatment at the primary operation by examining the appendix grossly and obtaining frozen section microscopic study of any suspicious tumor or ulceration.


Adenocarcinoma of the appendix: a clinicopathologic study.

Didolkar MS, Fanous N.

Dis Colon Rectum 1977 Mar;20(2):130-4 Abstract quote

Clinicopathologic correlation and survival were evaluated in 11 patients with adenocarcinomas of the appendix. This extremely rare tumor was seen most often in patients in the fifth decade of life. Acute appendicitis was the most common mode of presentation (8/11). A few patients (3/11) showed signs of distant metastases from an occult primary tumor in the appendix.


Primary malignant neoplasms of the appendix.

McCusker ME, Cote TR, Clegg LX, Sobin LH.

Department of Epidemiology and Preventive Medicine, University of Maryland, Baltimore, Maryland.

Cancer 2002 Jun 15;94(12):3307-12 Abstract quote

BACKGROUND
Cancer of the appendix is an uncommon disease that is rarely suspected rarely before surgery. Although several case series of these tumors have been published, little research has been anchored in population-based data on cancer of the appendix.

METHODS
This analysis included all actively followed cases of appendiceal neoplasms reported to the National Cancer Institute's Surveillance, Epidemiology and End-Results (SEER) program between 1973 and 1998. Tumors were classified as "colonic type" adenocarcinoma, mucinous adenocarcinoma, signet ring cell carcinoma, goblet cell carcinoid, and "malignant carcinoid" (SEER only collects data on carcinoids specifically classified as malignant). We compared incidence, overall survival and survival rates by extent of disease at diagnosis.

RESULTS
Between 1973 and 1998, 2117 appendiceal malignancies were reported to the SEER program, of which 1645 cases were included in the analysis. Age-adjusted incidence of cancer of the appendix was 0.12 cases per 1,000,000 people per year. Demographic characteristics of patients with goblet cell carcinoid tumors were midway between those of patients with malignant carcinoid and all types of adenocarcinomas. After controlling for age and extent of disease at diagnosis, the overall survival rate for patients diagnosed between 1983 and 1997 (n = 1061) was significantly worse for those with signet ring cell carcinoma than for those with any other tumor type (P < 0.01). In addition, overall survival rates were better for patients with malignant carcinoid (P = 0.01).

CONCLUSIONS
Demographic characteristics of patients with cancer of the appendix vary by histology. Except for signet ring cell carcinoma and malignant carcinoid, the extent of disease at time of diagnosis is a more important predictor of survival than histology.

TREATMENT  
SURGERY  


Adenocarcinoma of the vermiform appendix: retrospective study and literature review.

Panton ON, Bell GA, Owen DA.

Can J Surg 1983 May;26(3):276-9 Abstract quote

Adenocarcinoma of the vermiform appendix is a rare clinical entity, fewer than 200 cases having been reported.

The authors carried out a retrospective review over a 25-year period and found five patients admitted to the Vancouver General Hospital with primary appendiceal adenocarcinoma. Four other patients, initially reported as having appendiceal adenocarcinoma, were found after critical microscopic review to have had either benign disease or mucinous carcinoid. Primary epithelial neoplasms of the appendix demonstrate a wide variety of histologic types and because of the different clinical behaviour, an accurate diagnosis must be made.

For the benign tumours, appendectomy alone will suffice but for adenocarcinoma of the appendix, right hemicolectomy is recommended.


Adenocarcinoma of the appendix.

Ferro M, Anthony PP.

Dis Colon Rectum 1985 Jun;28(6):457-9 Abstract quote

Three cases of adenocarcinoma of the appendix are reported. All three patients presented with acute appendicitis and the tumors were diagnosed only on histologic examination of the excised appendix.

The first patient subsequently had a right hemicolectomy and was proven to have a Dukes' B tumor. The second patient probably had a Dukes' B also, but no further surgery was performed because of advanced presenile dementia. Advanced disease was found in the third patient. Analysis of 145 cases reported over the last ten years suggests that, unless the tumor is in Dukes' A stage, right hemicolectomy should be carried out if the patient is fit for radical surgery.

The overall prognosis appears to be the same as that for carcinoma of the colon.


Adenocarcinoma of the vermiform appendix.

Harris GJ, Urdaneta LF, Mitros FA.

Department of Surgery, University of Iowa, College of Medicine, Iowa City.

J Surg Oncol 1990 Aug;44(4):218-24 Abstract quote

Primary adenocarcinoma of the appendix is rare. Eleven patients with this rare neoplasm have been evaluated at our institution over a 50-year period.

We have reviewed the presentation and clinical course of these patients, and have compared them with those described in the literature. The presenting signs and symptoms, physical findings, and treatment were similar to those described in the literature. However, the 5-year survival of 20% is lower than most series, and reflects the advanced stage of disease at the time of diagnosis in this group of patients.

Despite the low 5-year survival, we feel that aggressive therapy (right hemicolectomy) is necessary to obtain long-term survival.

 

The natural history of surgically treated primary adenocarcinoma of the appendix.

Nitecki SS, Wolff BG, Schlinkert R, Sarr MG.

Department of Surgery, Mayo Clinic, Rochester, Minnesota.

Ann Surg 1994 Jan;219(1):51-7 Abstract quote

OBJECTIVE: The aim of this investigation was to determine the prognostic variables and optimal surgical procedure for patients with adenocarcinoma of the appendix.

SUMMARY BACKGROUND DATA: Primary adenocarcinoma of the appendix is a rare malignancy that constitutes less than 0.5% of all gastrointestinal neoplasms. However, the prognostic factors and the preferred surgical procedure and outcome are poorly understood.

METHODS: The authors reviewed their institutional experience from 1976 to 1992 in treating 94 consecutive patients with primary adenocarcinoma of the appendix. Patients with carcinoid tumors or those in whom the diagnosis of primary cecal cancer could not be ruled out were excluded from the study.

RESULTS: Fifty-two (55%) patients had the mucinous variety, of which 22 had pseudomyxoma peritonei; the other 45% had the colonic and adenocarcinoid types of tumor. The most common presentation was that of acute appendicitis. Interestingly, in no patients was the correct diagnosis made before surgery, and it was entertained intraoperatively in only 30 patients (32%). The cure 5-year survival rate was 55%, but it varied with stage (A, 100%; B, 67%; C, 50%; and D, 6%; p < 0.01) and with grade (I, 68%, and III, 7%; p < 0.01). Patients with the mucinous type had a better prognosis than those with the colonic type (p < 0.01). The survival rate was superior after right hemicolectomy versus appendectomy alone (68% vs. 20%, p < 0.001). Right hemicolectomy performed as a secondary procedure resulted in the upstaging of 38% of the patients' tumors. A second primary malignancy occurred in 33 patients (35%), of which 17 were located in the gastrointestinal tract.

CONCLUSIONS: Primary adenocarcinoma of the appendix should be treated by right hemicolectomy, even if it is a secondary procedure. Surveillance for synchronous or metachronous tumors, especially in the gastrointestinal tract, is warranted.

Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Eight Edition. Mosby 1996.
Sternberg S. Diagnostic Surgical Pathology. Third Edition. Lipincott Williams and Wilkins 1999.


Commonly Used Terms

Appendix


Last Updated 7/17/2002


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