Application of light microscopical and ultrastructural immunohistochemistry in the study of goblet cell carcinoid in the appendix

A fish model for the study of the relationship between neuroendocrine and immune cells in the intestinal epithelium: Silurus glanis infected with a tapeworm

Immunohistochemical, immunofluorescence and ultrastructural studies were conducted on a sub-population of 20 wels catfish Silurus glanis from a tributary of the River Po (Northern Italy). Fish were examined for the presence of ecto- and endo-parasites; in the intestine of 5 fish, 11 specimens of cestode Glanitaenia osculata were noted and was the only helminth species encountered. The architecture of intestine and its cellular features were nearly identical in either the uninfected S. glanis or in those harboring G. osculata. Near the site of worm's attachment, mucous cells, several mast cells (MCs), few neutrophils and some endocrine cells (ECs) were found to co-occur within the intestinal epithelium. MCs and neutrophils were abundant also in the submucosa. Immunohistochemical staining revealed that enteric ECs were immunoreactive to met-enkephalin, galanin and serotonin anti-bodies. The numbers of ECs, mucous cells and MCs were significantly higher in infected wels catfish (Mann-Whitney U test, p < 0.05). Dual immunofluorescence staining with the biotinylated lectin Sambucus nigra Agglutinin and the rabbit polyclonal anti-met-enkephalin or anti-serotonin, with parallel transmission electron microscopy, showed that ECs often made intimate contact with the mucous cells and epithelial MCs. The presence of numerous MCs in intestinal epithelium shows S. glanis to be an interesting model fish to study processes underlying intestinal inflammation elicited by an enteric worm. Immune cells, ECs and mucous cells of the intestinal epithelium have been described at the ultrastructural level and their possible functions and interactions together will be discussed.

Goblet cell carcinoids of the appendix: Tumor biology, mutations and management strategies

Malignant neoplasms of the appendix are rare and represent less than 1% of gastrointestinal cancers. Goblet cell carcinoids (GCC) tumors are a distinctive group of heterogeneous appendiceal neoplasm that exhibit unique clinical and pathologic features. This review focuses on the current diagnostic procedures, pathogenesis, possible signaling mechanisms and treatment options for GCC. Perspectives for future research are discussed. The tumor likely arises from pluripotent intestinal epithelial crypt base stem cells. Previous findings of Notch signaling as a tumor suppressor in Neuroendocrine tumors may have a similar role in this tumor too. Loss of Notch signaling may be the driver mutation with other successive downstream mutations likely favors them into progressing and behavior similar to poorly differentiated adenocarcinoma with minimal neuroendocrine differentiation. A multidisciplinary approach is suggested for optimal outcomes. Surgery remains the main treatment modality. Simple appendectomy may be sufficient in early stages while right hemicolectomy is recommended for advanced tumors. Cytoreductive surgery with heated intraperitoneal chemotherapy may improve survival in a select few with metastatic peritoneal disease. These tumors have an unpredictable behavior even in early stages and local recurrence and delayed metastases may be seen. Lifelong surveillance is warranted.

Enteric neuromodulators and mucus discharge in a fish infected with the intestinal helminth Pomphorhynchus laevis

BACKGROUND

In vertebrates, the presence of enteric worms can induce structural changes to the alimentary canal impacting on the neuroendocrine system, altering the proper functioning of the gastrointestinal tract and affecting the occurrence and relative density of endocrine cells (ECs). This account represents the first immunohistochemistry and ultrastructure-based study which documents the intimate relationship between the intestinal mucous cells and ECs in a fish-helminth system, investigating the potential effects of enteric neuromodulators on gut mucus secretion/discharge.

METHODS

A modified dual immunohisto- and histochemical staining technique was applied on intestinal sections from both infected and uninfected fish. Sections were incubated in antisera to a range of neuromodulators (i.e. leu-enkephalin, met-enkephalin, galanin and serotonin) and the glycoconjugate histochemistry of the mucous cells was determined using a subsequent alcian blue - periodic acid Schiff staining step. Dual fluorescent staining on sections prepared for confocal laser scanning microscopy and transmission electron microscopy were also used to document the relationship between ECs and mucous cells.

RESULTS

From a total of 26 specimens of Squalius cephalus sampled from the River Paglia, 16 (i.e. 62 %) specimens were found to harbour an infection of the acanthocephalan Pomphorhynchus laevis (average intensity of infection 9.2 ± 0.8 parasites host(-1), mean ± standard error). When acanthocephalans were present, the numbers of mucous cells (most notably those containing acidic or mixed glycoconjugates) and ECs secreting leu-enkephalin, met-enkephalin, galanin, serotonin were significantly higher than those seen on sections from uninfected fish. The relationship between met-enkephalin-like or serotonin-like ECs and lectin DBA positive mucous cells was demonstrated through a dual fluorescent staining. The presence of tight connections and desmosomes between mucous and ECs in transmission electron micrographs provides further evidence of this intimate relationship.

CONCLUSIONS

The presence of P. laevis induces an increase in the number of enteric ECs that are immunoreactive to leu- and met-enkephalin, galanin, and serotonin anti-sera. The mucous cells hyperplasia and enhanced mucus secretion in the helminth-infected intestines could be elicited by the increase in the number of ECs which release these regulatory substances.

Immunohistochemical features of the gastrointestinal tract tumors

Gastrointestinal tract tumors include a wide variety of vastly different tumors and on a whole are one of the most common malignancies in western countries. These tumors often present at late stages as distant metastases which are then biopsied and may be difficult to differentiate without the aid of immunohistochemical stains. With the exception of pancreatic and biliary tumors where there are no distinct immunohistochemical patterns, most gastrointestinal tumors can be differentiated by their unique immunohistochemical profile. As the size of biopsies decrease, the role of immunohistochemical stains will become even more important in determining the origin and differentiation of gastrointestinal tract tumors.

Goblet cell carcinoids at extraappendiceal locations of gastrointestinal tract: an underrecognized diagnostic pitfall

BACKGROUND

Goblet cell carcinoid (GCC) is a clinicopathologically distinctive tumor that typically arises in appendix and metastasizes frequently. Although rare cases of ostensibly primary extraappendiceal GCC (EGCC) have been reported, the distinction from extraappendiceal metastasis of occult appendiceal primary may be problematic and has not been dealt with systematically in literature.

METHODS

We reviewed our combined experience with EGCC at four North American hospitals and reevaluated all EGCC cases published in literature.

RESULTS

We encountered 16 cases that were initially reported as EGCC. Five cases presented with disseminated abdominopelvic spread, nine cases with mass lesions in stomach, ileum, cecum, ascending colon, hepatic flexure, sigmoid, and rectum. One case was found incidentally in an ascending colon adenomatous polyp. A negative appendix was confirmed in 2 (12.5%) cases, whereas a primary appendiceal GCC was discovered in 4 (25%) cases at a later date, and appendix was not available for review in 10 cases (62.5%). Of 10 cases of EGCC found in literature, the tumor sites included stomach, duodenum, jejunum, ileum, cecum, splenic flexure, and rectum. Primary appendiceal tumor was excluded histologically in one (10%), grossly in three (30%), and not at all in six (60%). Nine of our cases were initially misdiagnosed as signet-ring cell adenocarcinomas.

CONCLUSIONS

True EGCC is extremely rare. GCC found at locations other than appendix are most likely extraappendiceal presentations of appendiceal primary. A thorough review of the pathologic status of appendix should be a mandatory diagnostic criterion and should always be documented in the pathology reports.

Goblet cell carcinoid tumors of the appendix: An overview

Goblet cell carcinoid is an enigmatic and rare tumor involving the appendix almost exclusively. Since its identification in 1969, understanding of this disease has evolved greatly, but issues regarding its histogenesis, nomenclature and management are still conjectural. The published English language literature from 1966 to 2009 was retrieved via PubMed and reviewed. Various other names have been used for this entity such as adenocarcinoid, mucinous carcinoid, crypt cell carcinoma, and mucin-producing neuroendocrine tumor, although none have been found to be completely satisfactory or universally accepted. The tumor is thought to arise from pluripotent intestinal epithelial crypt-base stem cells by dual neuroendocrine and mucinous differentiation. GCCs present in the fifth to sixth decade and show no definite sex predominance. The most common clinical presentation is acute appendicitis, followed by abdominal pain and a mass. Fifty percent of the female patients present with ovarian metastases. The histologic hallmark of this entity is the presence of clusters of goblet cells in the lamina propria or submucosa stain for various neuroendocrine markers, though the intensity is often patchy. Atypia is usually minimal, but carcinomatous growth patterns may be seen. These may be of signet ring cell type or poorly differentiated adenocarcinoma. Recently molecular studies have shown these tumors to lack the signatures of adenocarcinoma but they have some changes similar to that of ileal carcinoids (allelic loss of chromosome 11q, 16q and 18q). The natural history of GCC is intermediate between carcinoids and adenocarcinomas of the appendix. The 5-year overall survival is 76%. The most important prognostic factor is the stage of disease. Appendectomy and right hemicolectomy are the main modalities of treatment, followed by adjuvant chemotherapy in select cases. There is some debate about the surgical approach for these tumors, and a summary of published series and recommendations are provided.

[Metastazation into the seminal vesicles due to primary goblet cell carcinoid of the vermiform appendix. An unusual diagnostic procedure of a seminal vesicle tumor]

We report on a remarkable diagnostic work up of suspect rectal palpation results in a 54-year-old patient. According to a transrectal ultrasound-guided punch biopsy the patient was suspected of having a carcinoma of the seminal vesicles and an aggressive operational approach was considered. After a median laparotomy a generalized peritoneal carcinomatosis was found. A goblet cell carcinoid of the vermiform appendix was identified as the primary tumor. This case report deals with metastazation of a primary goblet cell carcinoma into the seminal vesicles on both sides as an extremely rare reason for suspicious rectal palpation results. The tumor valency, diagnostic work up, therapy and further differential diagnoses are described.