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[The rabbit's appendix: an immunological model applied to the study of epithelial immunity (author's transl)].

The rabbit's appendix is a pecular lympho-epithelial formation as it includes both areas of thymus-dependent lymphocytes (the interpolated sieved lamina) and non-thymus-dependent lymph nodes. The epithelium joining the intestine lumen and the lymphatic tissue contains cells that become permeable at the contact of lymphocytes. These "tranformed" enterocytes are crossed by antigenic molecules, bacteria, yeasts and evolutive forms of coccidia. Lymphocytes within--as well as reticular cells below the epithelium--catch large molecules, especially antigens, thus having a share in humoral immunity. Just as those of the intestine, the enterocytes of the appendix glandular area are informed at the level of the areas of epithelial mitosis and become resistant to certain infections such as coccidosis. This particular form of immunity we have named "epithelial immunity". Thick sections provide ultrastructural views physically showing information exchanges. Intercellular exchange by contiguous endoplasmic reticular canaliculi at the interface of two cells have thus been demonstrated. They have been as clearly observed between two epithelial cells at between two cells of connective origin and again between an epiethelial cell and a lymphocyte.

Animals

[Surgical diseases of the veriform appendix].

Various diseases can symptomatically resemble appendicitis. It has been proved that luminal obstruction is the most frequent cause of inflammation of the appendix. There are various causes of obstruction, such as scars, foreign bodies, tumors, granulomas, and dysfunction of coecocolon. Every appendix should therefore be histologically examined. The operative indication for appendectomy should not only include the time factor, but also anamnesis, complaints, and clinical presentation. It is inconsiderate to perform appendectomy as a prophylaxis against appendicitis. Finally, it is surprising that there have been almost no experimental studies on pathogenesis of appendicitis.

Acute Disease

[Focal mucosal hyperplasia of the appendix (author's transl)].

On a 20-year-old male patient and on a 67-year-old female patient, we incidentally detected as histologicbioptic findings after routine appendectomy a focal mucosal hyperplasia of the appendix. Basing on these cases we give a survey on the literature pertaining to these rate cases of mucosal alterations of the appendix published up to now, and discuss the problems of these mucosal hyperplasias.

Adult

Invagination of the vermiform appendix. A report of two cases associated with endometriosis.

Two cases of invagination of the Vermiform appendix associated with endometriosis are presented. Classification, incidence, etiology, symptomatology, diagnosis and treatment are discussed. The literature is reviewed in brief, and it is concluded that the possibility of invagination of the Vermiform appendix should be considered in obsure abdominal cases with recurrent right lower quadrant pain.

Adult

A study of the histopathogenesis of carcinoid tumors of the small intestine and appendix.

A specimen from the small intestine with multiple (three) classic carcinoid tumors and one appendiceal carcinoid tumor displaying argentaffinity, argyrophilia (Grimelius stain), and serotonin and neuron specific enolase immunoreactivity was examined by light microscopy with regard to the tumor cell histopathogenesis. The smallest tumor (diameter 0.5 cm) from the small intestine was cut into 512 and the appendiceal tumor into 511 serial sections, which were stained with the argyrophil technique. In the small intestine an increased number of endocrine cells and small proliferating aggregates of endocrine cells were observed among nonendocrine enterocytes in the crypts of Lieberkühn. They seemed to grow initially inside the crypts and to later infiltrate through the basement membrane into the lamina propria of the mucosa. This finding suggests that classic carcinoid tumors of the small intestine develop from mucosal endocrine (enterochromaffin) cells. Since proliferating argentaffin cells were also seen in the mucosal crypts in one of the other two carcinoid tumors (2 cm in diameter) in the same intestine specimen, it is suggested that when multiple carcinoid tumors occur in the small intestine they arise from multiple sites. There was no apparent connection between the mucosal crypts and the carcinoid tumor of the appendix. Thus in this particular case, the appendiceal carcinoid tumor did not appear to derive from the mucosal endocrine cells but from the subepithelial endocrine cells that are present in the lamina propria and submucosa of the appendix wall. Supporting this view is the fact that S-100 protein immunoreactive cells are found both in close relation to subepithelial endocrine cells and as an integral component of appendiceal carcinoid tumors.

Appendiceal Neoplasms

Primary adenocarcinoma of the appendix with bilateral Krukenberg ovarian tumors.

An unusual case of a 22-year-old white female with known chronic ulcerative colitis presented with a several-day history of lower abdominal pain and a pelvic mass. Laparotomy revealed a primary carcinoma of the appendix with Krukenberg metastasis to both ovaries. Pathologically this tumor appeared to arise from an appendix which showed no evidence of chronic ulcerative colitis and therefore could not be associated with the above-mentioned entity.

Adenocarcinoma

Primary adenocarcinoma of the appendix: report of five cases and review of the literature.

Five patients with primary adenocarcinoma of the appendix are reported. All patients presented with symptoms resembling those of acute appendicitis or periappendicular abscess. In none of them was malignancy suspected prior to operation. It is advisable that every patient above 50 years of age presenting with symptoms of appendicitis undergo laparotomy, thus enabling a better exploration of the cecal region. If an appendiceal mass is present and frozen section shows malignancy, a right hemicolectomy should be performed. The prognosis of adenocarcinoma of the appendix is dismal as most patients present with an advanced stage of the disease.

Adenocarcinoma

The demonstration of a subset of carcinoid tumours of the appendix by in situ hybridization using synthetic probes to proglucagon mRNA.

Previous studies using immunohistochemistry have shown variable hormone production by carcinoid tumours of the appendix. In order to confirm the existence of a specific subset of these tumours, in situ hybridization using synthetic oligonucleotide probes to detect pre-proglucagon and pre-proinsulin mRNA was performed in formalin-fixed, paraffin-embedded material from eight tubular carcinoids, 12 insulin carcinoids, and two mucinous carcinoids. The results were correlated with standard silver and mucin stains. All tubular carcinoids but none of the insular or mucinous carcinoids contained proglucagon mRNA. Proinsulin mRNA was not detected in any of the tumours. Tubular carcinoids of the appendix constitute a definable subset of appendiceal carcinoids which have a similar distribution and prognosis to typical insular carcinoids and can be diagnosed on haematoxylin and eosin-stained sections confirmed by routine special stains. The main need for recognition is to avoid confusion with mucinous carcinoids, which have a worse prognosis and may require more aggressive treatment.

Appendiceal Neoplasms

Sigmoid invasion as a late complication of mucinous cystadenoma of the appendix. Report of a case.

A cystic mass arising from the right iliac fossa was an incidental finding at laparotomy and was treated conservatively after a biopsy had shown no evidence of malignancy. Nine years later the patient presented with shock and colonic bleeding. A large cystic lesion arising from the vermiform appendix and invading the sigmoid colon was found and excised. Histologic examination indicated that the underlying lesion was an inflamed mucinous cystadenoma of the appendix. Frank invasion of viscera by such lesions has not previously been described. Complications of such lesions and their association with other colonic neoplasms are discussed.

Aged

Adenocarcinoma of the appendix.

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

Preoperative colonoscopic diagnosis of villous adenoma of the appendix. Report of a case and review of the literature.

This case of villous adenoma of the appendix reported is unique by virtue of its having been diagnosed preoperatively using colonoscopy. Only 45 such lesions have been described previously, and a review of those cases reveals that 93 percent were discovered at appendectomy performed either incidentally or for acute appendicitis. The malignant potential of this entity is unknown and its treatment is controversial. Because of a report association between adenomas of the appendix and other gastrointestinal neoplasms, long-term surveillance is recommended.

Adenoma

Adenocarcinoma of the appendix: a clinicopathologic study.

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.

Adenocarcinoma

Primary carcinoma of the appendix.

Primary adenocarcinoma of the appendix is rare and less than 200 cases are on record. The present material consisted of 20 cases collected from different hospitals. The cases are described in respect of sex and age-distribution, symptoms, treatment and prognosis. Of 7 patients with malignant mucocele, 6 subjected to appendectomy only, were still alive 5 years after the operation. Of 12 patients with colonic type of adenocarcinoma, 3 had been treated with appendectomy only. Of these, 2 were still alive 5 years after the operation. The remaining 9 patients had undergone right hemicolectomy. Only one of them was alive 5 years after the operation. A compilation of a further 39 cases garnered from the literature, however, showed that 60% had survived at least 5 years after right hemicolectomy, compared with 46% after appendectomy alone. Appendectomy alone is probably a sufficiently radical operation for malignant mucocele provided the tumor has not grown through the submucosa and that it is confined to the tip of the appendix. Right hemicolectomy is indicated for the colonic type of adenocarcinoma.

Adenocarcinoma

Primary adenocarcinoma of the appendix.

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

Argyrophil, non-argentaffin carcinoids of the appendix vermiformis. Immunohistochemical and ultrastructural studies.

Five argyrophil, non-argentaffin classical carcinoids of the appendix were found in 19 appendiceal classical carcinoids and were investigated histochemically, immunohistochemically and ultrastructurally. All tumors consisted entirely of argyrophil cells. Three of the five carcinoids were composed almost totally of peptide YY cells and were negative for serotonin. One of them consisted of peptide YY cells (60%), somatostatin cells (40%), and a few cells with glucagon-like immunoreactivity (GLI). The remaining one without peptides was homogeneously immunoreactive for serotonin alone. Ultrastructurally, each of the four peptide-positive carcinoids was composed of one kind of endocrine cell type with round secretory granules. Average diameter of granules were 150, 160, 190, and 210 nm, respectively. The non-argentaffin, serotonin-positive carcinoid showed predominant round secretory granules and a few irregular ones, both being 150 nm in largest diameter. It is suggested that the argyrophil, non-argentaffin carcinoids of the appendix are subdivided into two groups; carcinoids composed mainly of peptide (especially, peptide YY)-positive cells with round granules of D1 and/or L cell type and those of serotonin-positive cells with pleomorphic granules of ECn cell type.

Adolescent

Adenocarcinoma of the vermiform appendix. A population study.

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.

Adenocarcinoma