Adenocarcinoma of the vermiform appendix. A population study

Incidence of Appendiceal Malignancies in Sweden Between 1970 and 2012

BACKGROUND

There is limited knowledge about the epidemiology of the major histological subtypes of appendiceal malignancy: adenocarcinoma and neuroendocrine neoplasm of the appendix (A-NEN). The aims of this national cohort study were to assess the prevalence, incidence and trends of appendiceal malignancies in Sweden.

METHOD

All individuals who underwent appendicectomy and all diagnosed with appendiceal malignancy from 1970 to 2012 were identified from the National Patient Register and the Swedish Cancer Registry. Demographic data of the background population were obtained from Statistics Sweden. The incidence rate (IR) and the prevalence of appendiceal malignancy per performed appendicectomy were calculated.

RESULTS

We identified 3774 patients with appendiceal malignancy. IR of A-NEN was 5.8/10⁶ person-years with a peak of 8.4/10⁶ at age 20-30 years, whereafter it plateaued at a somewhat lower level. IR for adenocarcinoma was 3.7/10⁶ person-years, starting at a very low level among the youngest and increasing to 15.4/10⁶ at age 80-89 years. The IR of adenocarcinoma increased from 2.6/10⁶ in 1970-1979 to 5.4/10⁶ in 2010-2012. The IR of A-NEN was stable during the study period. The prevalence per appendicectomy was low for both types of malignancies among the young but increased with age, most dramatically for adenocarcinoma. There was a trend during the study period towards more extensive surgery.

CONCLUSION

Adenocarcinoma is most common and increasing in the elderly, whereas A-NEN affects all ages with a peak in young age. This peak probably reflects removal of occult A-NEN due to the higher appendicectomy frequency in the young.

Unexpected Histopathological Findings in Appendectomy Specimens: a Retrospective Study of 1627 Cases

Pathologic evaluation of the appendix after appendectomy is routine and can occasionally identify unexpected findings. The aim of the present study was to determine the incidence and type of pathologic diagnoses found in appendectomy specimens at our institution. The clinicopathological data of 1627 patients who underwent appendectomies for presumed acute appendicitis from January 2008 to October 2014 were reviewed retrospectively. There were 986 men and 641 women (sex ratio M/F = 1.5) aged between 16 months and 90 years (mean = 30 years). All patients underwent appendectomy (either open or laparoscopic). Histological examination of the surgical specimen showed acute inflammation of the appendix in 1455 cases (89.42 %), fibrosed appendix in 37 cases (2.27 %), and Enterobius vermicularis (n = 23). In 101 cases (6.2 %), the appendix was histologically normal. Incidental unexpected pathological diagnoses were noted in 57 appendectomy specimens. They included pinworm (n = 23), mucinous neoplasms (n = 12), neuroendocrine tumors (NET) (n = 8), adenocarcinoma (n = 2), granulomatous inflammation (n = 5), tuberculosis (n = 2), hyperplastic polyp (n = 1), tubular adenoma (n = 1), diverticulitis (n = 1), endometriosis (n = 1), and actinomycosis (n = 1). The routine histopathological examination of the appendix is of value for identifying unsuspected conditions requiring further postoperative management. Gross examination alone does not appear to be a good indicator of an unexpected finding on microscopic exam. It is recommended that in order to avoid misdiagnoses, all appendices should be histopathologically examined.

Laparoscopic diagnosis of adenocarcinoma of the appendix mimicking serous papillary adenocarcinoma of the peritoneum

Primary carcinoma of the vermiform appendix is a rare disease with few clinical symptoms. Accordingly, preoperative diagnosis of appendiceal cancer is challenging because of the lack of specific symptoms. We herein report a case of appendicular adenocarcinoma found unexpectedly during laparoscopic surgery in a 69-year-old Japanese female patient diagnosed with serous papillary adenocarcinoma, in order to determine whether optimal cytoreduction could successfully be achieved at the time of primary surgery. We performed diagnostic laparoscopic surgery in order to make a correct diagnosis based on the histological tissue. The vermiform appendix was found to contain a tumor measuring 1.5 cm wide and 4.5 cm long. Laparoscopic appendectomy, partial omentectomy, and partial resection of the lesion in the peritoneum were performed. The histological diagnosis was mucinous adenocarcinoma of the vermiform appendix, and the stage was T4NxM1. The patient received adjuvant chemotherapy with mFOLFOX 6 (5FU, leucovorin, and oxaliplatin). She achieved stable disease and was alive with disease eleven months after surgery. We therefore recommend that gynecologists should not rule out the possibility of appendiceal cancer, even in cases with preoperative findings similar to those of serous papillary adenocarcinoma of the peritoneum with peritoneal disseminated tumors.

Frequent GNAS mutations in low-grade appendiceal mucinous neoplasms

Background:

The molecular basis for the development of appendiceal mucinous tumours, which can be a cause of pseudomyxoma peritonei, remains largely unknown.

Methods:

Thirty-five appendiceal mucinous neoplasms were analysed for GNAS and KRAS mutations. A functional analysis of mutant GNAS was performed using a colorectal cancer cell line.

Results:

A mutational analysis identified activating GNAS mutations in 16 of 32 low-grade appendiceal mucinous neoplasms (LAMNs) but in none of three mucinous adenocarcinomas (MACs). KRAS mutations were found in 30 LAMNs and in all MACs. We additionally analysed a total of 186 extra-appendiceal mucinous tumours and found that GNAS mutations were highly prevalent in intraductal papillary mucinous tumours of the pancreas (88%) but were rare or absent in mucinous tumours of the colorectum, ovary, lung and breast (0–9%). The prevalence of KRAS mutations was quite variable among the tumours. The introduction of the mutant GNAS into a colorectal cancer cell line markedly induced MUC2 and MUC5AC expression, but did not promote cell growth either in vitro or in vivo.

Conclusion:

Activating GNAS mutations are a frequent and characteristic genetic abnormality of LAMN. Mutant GNAS might play a direct role in the prominent mucin production that is a hallmark of LAMN.

Clinicopathological features and the outcome of surgical management for adenocarcinoma of the appendix

AIM: To present a comprehensive analysis of incidence, clinicopathological features, appropriateness of surgical procedures, and survival for adenocarcinoma of the appendix.

METHODS: A retrospective case analysis was conducted for the 10-year period 1998-2008. All patients diagnosed with adenocarcinoma of the appendix were analyzed for their demographics details, clinical features, tumor incidence and characteristics, tumor stage, surgical procedures performed, and their survival.

RESULTS: Nine thousand three hundred and twenty-three patients underwent appendectomies during the study period, and of these, 10 (0.1%: 8 men and 2 women with a mean age of 53.1 years, age range 21-83 years) were found to have primary adenocarcinoma of the appendix. Appendicular neoplasia was not suspected pre-operatively in any of the patients. Six (60%) patients underwent secondary right hemicolectomy. Four (40%) cases had appendectomy alone, and two of them died, whereas all those who underwent right hemicolectomy are alive and disease free. Five (50%) were reported to have grade 1 disease, three (30%) grade 2, and two (20%) grade 3 with mean survival of 34, 48, and 22 mo, respectively. Six (60%) patients presented with advanced disease (Duke’s C and D). At the end of follow up (mean period: 37.9 mo), eight patients are alive and disease free at the end of follow up. Overall mean survival was 36.3 mo (confidence interval; 16%-56%) with 41.3 and 16 mo for men and women, respectively. Mean survival for those with and without lymph node involvement was 33.6 and 40.2 mo, respectively. Right hemicolectomy gave better results than appendectomy alone, although the difference was not statistically significant due to the small number of cases.

CONCLUSION: Adenocarcinoma of the appendix is extremely rare neoplasm with varied presentations, and is usually advanced when diagnosed. Right hemicolectomy is the treatment of choice for such tumors.

Adenocarcinoma of the appendix with a fistula to the urinary bladder

Adenocarcinoma of the vermiform appendix is a rare disease that constitutes less than 0.5% of all gastrointestinal malignancies. A patient was admitted with abdominal discomfort and urinary frequency but no symptoms suggestive of enterovesical fistula, e.g. pneumaturia or urinary tract infection. She was diagnosed with adenocarcinoma of the appendix with a fistula to the urinary bladder.

Malignant neoplasms of the appendix

BACKGROUND

Appendiceal neoplasms, first described in 1882, are still rare, with pre-operative diagnosis invariably difficult. We present our 10-year experience of these lesions with a review of current epidemiology, pathology and treatment modalities.

MATERIALS AND METHODS

A retrospective histopathological review of all appendicectomy specimens was completed between April 1994 and December 2003 to identify patients diagnosed with malignant neoplasms. Patient demographics, operative details, histopathology and clinical outcomes were obtained from case notes. A literature search of the PubMed database was then performed using the medical search headings; appendix, tumour, neoplasm and malignancy.

RESULTS

Twenty-two patients (eight men) were identified during the study period, with no age difference between gender (mean age in women 58, range 14-83 vs mean age in men 55, range 16-78). Eleven patients were found to have carcinoid-type tumours, eight patients with adenocarcinomas and three patients with lymphomas. Other appendiceal pathologies were identified after appendicectomies, hemicolectomy and oophorectomy. Mean follow-up was 41 months (range 1-125 months). Fourteen patients were alive at the end of follow-up. Patients with classical carcinoid tumours (CCT) had better outcomes than patients with the goblet cell carcinoid, adenocarcinoma and lymphoma.

CONCLUSIONS

From our own experience and a subsequent review of the literature, we recommend right hemicolectomy as the treatment of choice for all malignant appendiceal neoplasms, except for small CCT less than 2 cm in diameter at the tip of the appendix, with a low proliferative index, without angiolymphatic or mesoappendiceal extension. Further adjuvant therapy should be considered after oncological assessment.

Appendiceal neoplasms and pseudomyxoma peritonei: a population based study

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare disease with an estimated incidence of 1 per million per year, and is thought to originate usually from an appendiceal mucinous epithelial neoplasm. However it is not known exactly how often these neoplasms lead to PMP. The aim of this study is to investigate the incidence of both lesions and their relation.

METHODS

The nationwide pathology database of the Netherlands (PALGA) was searched for the incidence of all appendectomies, the incidence of primary epithelial appendiceal lesions and the incidence and pathology history of patients with PMP. All regarded the 10-year period of 1995-2005.

RESULTS

In the 10-year period 167,744 appendectomies were performed in the Netherlands. An appendiceal lesion was found in 1482 appendiceal specimens (0.9%). Nine percent of these patients developed PMP. Coincidentally, an additional epithelial colonic neoplasm was found in 13% of patients with an appendiceal epithelial lesion. A mucinous epithelial neoplasm was identified in 0.3% (73% benign, 27% malignant) of appendiceal specimens and 20% of these patients developed PMP. For mucocele and non-mucinous neoplasm the association with PMP was only 2% and 3%, respectively. From the nationwide database 267 patients (62 men and 205 women) with PMP were identified, which demonstrates an incidence of PMP in the Netherlands approaching 2 per million per year. The primary site was identified in 68% and dominated by the appendix (82%).

CONCLUSIONS

Primary epithelial lesions of the appendix are rare. One third of these lesions are mucinous epithelial neoplasms and especially these tumours may progress into PMP. The incidence of PMP seems to be higher than thought before. Furthermore there is a considerable risk of an additional colonic epithelial neoplasm in patients with an epithelial neoplasm at appendectomy.

Recurrent gastric adenocarcinoma presenting as acute appendicitis: a case report

We report a case of acute appendicitis due to recurrent metastatic gastric adenocarcinoma involving only appendix, without the evidence of abdominal carcinomatosis 2 years after initial diagnosis of the primary gastric lesion. This case, in contrast to other previously reported cases that carried a dismal prognosis, had survived without tumour recurrent for more than 1 year after appendectomy, while this report was made.

Cancer of appendix as a presenting feature of Crohn's disease

Appendiceal neoplasms are rare. Colonic malignancies, including appendiceal carcinomas, have been rarely reported in Crohn's disease patients. The involvement of the appendix in Crohn's disease is not often seen. We report an interesting case in which a caecal Crohn's disease patient presented for the first time with an appendiceal adenocarcinoma.

Primary malignant neoplasms of the appendix: a population-based study from the surveillance, epidemiology and end-results program, 1973-1998

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.

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

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.

Laparoscopic management of pseudomyxoma peritonei secondary to adenocarcinoma of the appendix

Pseudomyxoma peritonei is a rare disease in which the abdominal cavity fills with thick mucoid material secondary to either benign or malignant conditions. We discuss a case where pseudomyxoma peritonei secondary to adenocarcinoma of the appendix was diagnosed and managed laparoscopically. The laparoscopic approach allows thorough exploration of the abdomen, as well as irrigation and aspiration of the thick mucinous material using a 10-mm suction cannula and the instillation of mucolytic agents such as 5% dextrose solution. Appendectomy or right hemicolectomy can be performed with minimal disturbance of the anterior abdominal wall, thus minimizing future adhesions as well as possible tumor-cell implantation. Intraperitoneal catheters for chemotherapy can be placed easily through the port sites. These measures offer an alternative to radical peritoneal dissection and can be accomplished during the initial laparoscopic exploration.

Neoplastic lesions of the appendix

Neoplasms occur in 0.5 per cent of appendices. Ultrasonography or computed tomography is beneficial, but preoperative detection is rare. At operation, the diagnosis is considered in under half of cases. Mucocele, localized pseudomyxoma peritonei, benign tumours and most appendiceal carcinoids are cured by appendicectomy alone. Right hemicolectomy is indicated for: (1) invasive adenocarcinoma; (2) tumours close to the caecum; (3) lesions larger than 2 cm; (4) mucin production; (5) invasion of the lymphatics, serosa or mesoappendix; and (6) cellular pleomorphism with a high mitotic rate. Tumours of 1-2 cm, small mucinous carcinoids, adenocarcinoma confined to the mucosa, and tumours in children may be treated by appendicectomy alone at the surgeon's discretion. The 5-year survival rate associated with classical carcinoid is more than 90 per cent. The prognosis of mucinous carcinoid is intermediate between that of classical carcinoid and well differentiated adenocarcinoma. The prognosis of adenocarcinoma is determined by Dukes' stage and is similar, stage for stage, to that of colorectal carcinoma.

Flow cytometric DNA analysis of adenocarcinomas of the vermiform appendix. Brief report

The DNA ploidy status and S-phase fraction of eight adenocarcinomas of the vermiform appendix diagnosed in Iceland during 1974-1990 were analyzed by flow cytometry. Four cases were classified as Dukes' stage B2 and four cases as Dukes' stage D. Seven tumors were diploid and one was aneuploid. The DNA aneuploid tumor was the only one which metastasized outside the abdominal cavity. The S-phase fraction in general was low. The results of this study do not indicate any significant correlation between ploidy status and clinical behavior.