Pathologic classification and clinical behavior of the spectrum of goblet cell carcinoid tumors of the appendix. Am J Surg Pathol. 2008;32:1429-1443. [PMID: 18685490 DOI: 10.1097/pas.0b013e31817f1816]

Perforation in appendiceal well-differentiated carcinoid and goblet cell tumors: impact on prognosis? A systematic review

BACKGROUND

Carcinoid tumors are the most common malignant lesions arising from Appendix and are mostly found incidentally during surgery for appendicitis. Perforation of Appendix occurs in 10-20% of cases with appendicitis. Currently, no guidelines exist for the treatment of perforated carcinoids of Appendix.

METHODS

A systematic literature search was performed to identify relevant articles on classical carcinoid or goblet cell carcinoid of Appendix in an attempt to evaluate the impact of perforation on management and prognosis. All articles on carcinoids reporting perforation of Appendix were included.

RESULTS

In total, 23 articles on carcinoid of Appendix with an associated perforation were found. Perforation was never investigated or mentioned as a possible negative factor on recurrence or prognosis. Among a total of 103 patients with classical carcinoids and associated perforation, no peritoneal recurrence or death was described, although follow-up data were often unspecified or scarce. Among a total of 18 goblet cell carcinoids with perforation, metastatic spread to the peritoneum was described in one case and two tumor-related deaths occurred among these cases. No specific relation to perforation could be distilled.

CONCLUSIONS

The best available evidence suggests that perforation has no influence on prognosis of classical appendiceal carcinoids. In contrast, peritoneal carcinomatosis is much more common in goblet cell carcinoids but the true impact of perforation remains unclear. Careful follow-up should therefore be considered in these cases.

The 2010 WHO classification of digestive neuroendocrine neoplasms: a critical appraisal four years after its introduction

This paper briefly illustrates the basis, rules of application, and present outcome of the current World Health Organization (WHO) classification for neuroendocrine neoplasms. Established in 2010 upon the proposal from the European Neuroendocrine Tumor Society (ENETS), the WHO 2010 fostered some definitional changes (most notably the use of neuroendocrine tumor (NET) instead of carcinoid) and indicated the tools of grading and staging. Specific rules for its application were also defined. The data generated from the use of WHO 2010 classification substantially endorsed its rules and prognostic efficacy. In addition, the application demonstrated some issues, among which are the possible re-definition of the cutoff for grading G1 vs G2, as well as the possible identification of cases with somewhat different clinical behavior within the G3 neuroendocrine cancer class. Overall, since the recent introduction of WHO 2010 grading and staging, it appears wise to keep the current descriptors to avoid unnecessary confusion and to generate comparable data. Homogenous data on large series are ultimately needed to solve such issues.

Cytologic features of pancreatic adenocarcinoma with "vacuolated cell pattern." report of a case diagnosed by endoscopic ultrasound-guided fine-needle aspiration

The "vacuolated cell pattern" has only been recently described as a distinct morphologic variant of pancreatobiliary adenocarcinoma. Herein, we report the endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) cytologic features of a case of pancreatic adenocarcinoma with "vacuolated cell pattern" occurring in a 60-year-old man. The aspirate smears and cell block sections from the EUS-FNA of a 23.5 mm hypoechoic pancreatic head mass were highly cellular, showing variably-sized crowded three-dimensional cell clusters, flat sheets, and numerous highly atypical single cells. The background was bloody and showed necrotic debris, but no discernible mucus. The most striking feature of the aspirate was the presence of numerous very large (20-50 µm) vacuoles, occupying the entire cytoplasm, pushing the nuclei to the side and indenting them, that imparted a cribriform appearance to the sheets of neoplastic cells. The non-vacuolated neoplastic cells were large, had abundant dense (squamoid) cytoplasm, irregularly contoured hyperchromatic nuclei, and prominent macronucleoli. Histologic evaluation of the pancreatectomy specimen showed a "vacuolated cell pattern" adenocarcinoma composed of poorly formed glands, solid sheets, and infiltrating single cells with pleomorphic nuclei and large cytoplasmic vacuoles. To our knowledge, this is the first report describing the cytologic features of this rather uncommon morphologic variant of pancreatic adenocarcinoma. Recognition of this morphologic variant of pancreatic adenocarcinoma in ESU-FNA samples allows its differentiation from primary and metastatic signet-ring cell carcinomas.

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy: an emerging treatment option for advanced goblet cell tumors of the appendix

BACKGROUND

The debate remains whether appendiceal goblet cell cancers behave as classical carcinoid or adenocarcinoma. Treatment options are unclear and reports of outcomes are scarce. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS+HIPEC) is considered optimal treatment for peritoneal involvement of other epithelial appendiceal tumors.

METHODS

Prospective cohorts of patients treated for advanced appendiceal tumors from three peritoneal malignancy centres were collected (1994-2011). All patients underwent complete CRS+HIPEC, when possible, or tumor debulking. Demographic and outcome data for patients with goblet cell cancers were compared to patients with low- or high-grade epithelial appendiceal tumors treated during the same time period.

RESULTS

Details on 45 goblet cell cancer patients were compared to 708 patients with epithelial appendix lesions. In the goblet cell group, 57.8 % were female, median age was 53 years, median peritoneal cancer index (PCI) was 24, and CRS+HIPEC was achieved in 71.1 %. These details were similar in patients with low- or high-grade epithelial tumors. Lymph nodes were involved in 52 % of goblet cell patients, similar to rates in high-grade cancers, but significantly higher than in low-grade lesions (6.4 %; p < 0.001). At 3 years, overall survival (OS) was 63.4 % for goblet cell patients, intermediate between that for high-grade (40.4-52.2 %) and low-grade (80.6 %) tumors. On multivariate analysis, tumor histology, PCI, and achievement of CRS+HIPEC were independently associated with OS.

CONCLUSIONS

This data supports the concept that appendiceal goblet cell cancers behave more as high-grade adenocarcinomas than as low-grade lesions. These patients have reasonable long-term survival when treated using CRS+HIPEC, and this strategy should be considered.

Appendiceal goblet cell carcinoid and mucinous neoplasms are closely associated tumors: lessons from their coexistence in primary tumors and concurrence in peritoneal dissemination

BACKGROUND

Goblet cell carcinoid (GCC) and appendiceal mucinous neoplasms (AMNs) are considered as different appendiceal tumors. Coexistence of both tumors was occasionally noted. We further observed the concurrence in both primary tumors and their peritoneal dissemination, that is, peritoneal carcinomatosis (PC) including pseudomyxoma peritonei (PMP).

METHODS

Review of our 10-year file identified two subgroups of cases with such concurrence. Group 1 is 14 cases of PC/PMP treated by surgical cytoreduction. Morphologic components of GCC, low-grade mucinous neoplasm (LMN), mucinous adenocarcinoma (MCA), and non-mucinous adenocarcinoma (NMCA) were identified separately in different organs/tissues. Group 2 is eight cases of localized primary tumors of appendix and ileocecal junction.

RESULTS

In Group 1, primary tumors (11 GCC, 1 GCC + LMN, 1 MCA, 1 NMCA) were identified in appendix (13) and in rectum (1). Further review identified mixed morphologic components in 7/12 GCC cases, including GCC + LMN (2), GCC + MCA (2), GCC + NMCA (1), and GCC + MCA + NMCA (2). Over peritoneal dissemination, GCC and/or other components were coexistent at different sites and in variable combinations. In Group 2, primary tumors were initially diagnosed as GCC (7) and MCA (1). Further review identified mixed components in all cases, including GCC + LMN (3), GCC + LMN + MCA (3), GCC + MCA + NMCA (2).

CONCLUSIONS

GCC may present as a component mixed with AMNs and even with conventional adenocarcinoma in both primary tumors and metastatic lesions. AMN in any given single case may show a wide morphologic spectrum. GCC and AMN may share a common tumor stem cell with potential of multiple lineage differentiations.

Metastatic appendiceal goblet cell carcinoid masquerading as mucinous adenocarcinoma in effusion cytology: A diagnostic pitfall

Goblet cell carcinoids are rare tumors of appendix having a mixed phenotype, with partial neuroendocrine differentiation and intestinal type goblet cell morphology. The reported incidence of this tumor is still limited. Till now, only two cases of metastatic goblet cell appendiceal carcinoid on effusion cytology have been reported in literature. We describe the clinico-pathological details and lay stress on fluid cytology of metastatic goblet cell carcinoid to ascitic fluid.

Histopathology of gastrointestinal neuroendocrine neoplasms

Gastrointestinal neuroendocrine neoplasms (GI-NENs) arise from neuroendocrine cells distributed mainly in the mucosa and submucosa of the gastrointestinal tract. In 2010, the World Health Organization (WHO) classification of NENs of the digestive system was changed, categorizing these tumors as grade 1 neuroendocrine tumor (NET), grade-2NET, neuroendocrine carcinoma (large- or small-cell type), or mixed adenoneuroendocrine carcinoma (MANEC). Such a classification is based on the Ki-67 index and mitotic count in histological material. For the accurate pathological diagnosis and grading of NENs, it is important to clearly recognize the characteristic histological features of GI-NENs and to understand the correct method of counting Ki-67 and mitoses. In this review, we focus on the histopathological features of GI-NENs, particularly regarding biopsy and cytological diagnoses, neuroendocrine markers, genetic and molecular features, and the evaluation of the Ki-67 index and mitotic count. In addition, we will address the histological features of GI-NEN in specific organs.

Goblet cell carcinoids of the appendix

Goblet cell carcinoid (GCC) tumors are a rare subgroup of neuroendocrine tumors almost exclusively originating in the appendix. The tumor most often presents in the fifth or sixth decade with a clinical picture of appendicitis or in advanced cases an abdominal mass associated with abdominal pain. Histologically tumors are most often positive for chromogranin A and synaptophysin, however, less homogenous than for classic appendix carcinoids. The malignant potential is higher than that for the classic appendix carcinoids due to local spread and distant metastases at diagnosis and the proliferation markers (Ki67 index) may determine prognosis. Octreotide receptor scintigraphy is usually negative while CT/MRI scans may be useful. Chromogranin A is usually negative and other biomarkers related to the mucinous component or the tumor (CEA, CA-19-9, and CA-125) may be used. Surgery is the main treatment with appendectomy and right hemicolectomy while patients with disseminated disease should be treated with chemotherapy. Overall 5-year survival is approximately 75%. The diagnosis and treatment of GCC tumorss should be restricted to high volume NET centers in order to accumulate knowledge and improve survival in GCC NET patients. The aim of this paper is to update on epidemiology, clinical presentation, and diagnostic markers including Ki67 index, treatment, and survival.

Goblet cell carcinoid in a patient with neurofibromatosis type 1: a rare combination

Neuroendocrine tumors are rare tumors primarily located in the gastrointestinal tract. Goblet cell carcinoid is a rare subgroup of neuroendocrine tumors located in the appendix. Neurofibromatosis type 1 is an autosomal dominant disorder caused by a mutation in the NF1 gene. Patients with neurofibromatosis type 1 have an increased incidence of typical neuroendocrine tumors, but it is unknown if this is the case with goblet cell carcinoids. We describe a patient with both neurofibromatosis type 1 and goblet cell carcinoid, that according to literature would occur in 0.00017 per million per year. This may suggest a previously unknown association between neurofibromatosis type 1 and goblet cell carcinoids.

Surgery for GEP-NETs

Surgery is the only treatment that may cure the patient with gastroentero-pancreatic (GEP) neuroendocrine tumours (NET) and neuroendocrine carcinomas (NEC) and should always be considered as first line treatment if R0/R1 resection can be achieved. The surgical and interventional procedures for GEP-NET are accordingly described below. Life-long follow-up should be performed in almost all patients at a specialized NET center.

Goblet cell carcinoid neoplasm of the appendix: clinical and CT features

PURPOSE

To describe the clinical and CT imaging features of goblet cell carcinoid (GCC) neoplasm of the appendix.

METHODS AND MATERIALS

A computer search of pathology and radiology records over a 19-year period at our two institutions was performed using the search string "goblet". In the patients with appendiceal GCC neoplasms who had abdominopelvic CT, imaging findings were categorized, blinded to gross and surgical description, as: "Appendicitis", "Prominent appendix without peri-appendiceal infiltration", "Mass" or "Normal appendix". The CT appearance was correlated with an accepted pathological classification of: low grade GCC, signet ring cell adenocarcinoma ex, and poorly differentiated adenocarcinoma ex GCC group.

RESULTS

Twenty-seven patients (age range, 28-80 years; mean age, 52 years; 15 female, 12 male) with pathology-proven appendiceal GCC neoplasm had CT scans that were reviewed. Patients presented with acute appendicitis (n=12), abdominal pain not typical for appendicitis (n=14) and incidental finding (n=1). CT imaging showed 9 Appendicitis, 9 Prominent appendices without peri-appendiceal infiltration, 7 Masses and 2 Normal appendices. Appendicitis (8/9) usually correlated with typical low grade GCC on pathology. In contrast, the majority of Masses and Prominent Appendices without peri-appendiceal infiltration were pathologically confirmed to be signet ring cell adenocarcinoma ex GCC. Poorly differentiated adenocarcinoma ex GCC was seen in only a small minority of patients. Hyperattenuation of the appendiceal neoplasm was seen in a majority of cases.

CONCLUSIONS

GCC neoplasm of the appendix should be considered in the differential diagnosis in patients with primary appendiceal malignancy. Our cases demonstrated close correlation between our predefined CT pattern and the pathological classification.

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.

[Gastrointestinal mixed adenoneuroendocrine carcinomas. An attempt at classification of mixed cancers]

Mixed adenoneuroendocrine carcinomas (MANECs) are a challenge for the diagnostics and the concept of a histogenetic tumor typing. They are classified into three malignant subgroups: high grade malignant MANECs combine an adenoma or adenocarcinoma with a small cell or large cell neuroendocrine carcinoma, intermediate grade malignant MANECs consist of a neuroendocrine tumor (NET grade 1 or 2), often a globlet cell carcinoid and a poorly differentiated adenocarcinoma or diffuse carcinoma of signet ring cell type. The prototype of a low grade malignant MANEC is the globlet cell carcinoid. Molecular analysis indicates a common clonal origin of the different components in MANECs. The prognosis is determined by the most aggressive tumor component. The pathogenesis of MANECs is apparently a sequence of increasing malignant transformation which leads either from an adenoma/adenocarcinoma to a small or large cell neuroendocrine carcinoma or from a neuroendocrine tumor (NET), often a globlet cell carcinoid to a poorly differentiated adenocarcinoma or a diffuse carcinoma of signet ring cell type.

Varying malignant potential of appendiceal neuroendocrine tumors: importance of histologic subtype

BACKGROUND

Neuroendocrine tumors (NETs) of the appendix include malignant carcinoid tumor (MCT), goblet cell carcinoid (GCT), and composite goblet cell carcinoid-adenocarcinoma (CGCC-A).

METHODS

We compared characteristics and outcomes of these histologic subtypes. Patients with appendiceal NETs were identified from the National Cancer Database (1998-2007). Descriptive statistics were used to compare cohorts and associations between clinicopathologic factors and overall survival (OS) were examined using Cox proportional hazards models.

RESULTS

A total of 2,812 patients with appendiceal NETs were identified. The most common histologic subtype was GCT (59.6%), followed by MCT (32.1%), CGCC-A (6.9%), and others (1.4%). CGCC-A had a significantly higher incidence of lymph node metastases (odds ratio [OR], 3.2; 95% confidence interval [CI], 2.1-4.8) and distant metastases (OR, 6.0; 95% CI = 3.8-9.3) than GCT. The 5-year OS was 86.3% (95% CI, 81.4-89.9) for MCT, 77.6% (95% CI, 74.0-80.8) for GCT, and 56.3% (95% CI, 42.1-68.4) for CGCC-A (P < 0.0001).

CONCLUSION

Appendiceal NETs represent a spectrum of disease with varying malignant potential: MCT (low), GCT (intermediate), and CGCC-A (high). GCTs represent the most common subtype, whereas CGCC-As place the patient at highest risk for regional and distant metastases and have the worst prognosis.

Appendiceal goblet cell carcinoid tumour: a case of unexpected lung metastasis

Goblet cell carcinoid tumours are often considered a subset of appendiceal neuroendocrine tumours which behave more aggressively. They usually metastasize through transcoelomic/peritoneal invasion and common sites include the ovaries, peritoneum, and liver. Metastases may have goblet cell carcinoid, signet ring cell carcinoma or classic carcinoid histology. We report the first case in the literature of a patient with a goblet cell carcinoid with lung metastasis, which was associated with unfavourable outcome.

[Rectal goblet cell carcinoid. Primary tumor or metastasis?]

Goblet cell carcinoids are biphasic neoplasms of the gastrointestinal tract composed of a glandular and neuroendocrine differentiation. Typically, goblet cell carcinoids are localized in the vermiform appendix. We report the case of a 60-year-old female patient with the diagnosis of a 1.2-cm rectal goblet cell carcinoid tumor discovered during prophylactic proctocolonoscopy. Because of the known aggressive behavior of this entity, a rectosigmoidectomy was performed. The preoperative staging revealed neither local nor systemic spread. After 8 months, the patient is in good health. As a primary tumor of the extraappendiceal gastrointestinal tract, goblet cell carcinoids are a rarity. It is generally recommended to exclude metastasis of a primary appendiceal neoplasm. However, since the patient underwent an appendectomy in 1974, primary origin in the rectum is favored.

[Neuroendocrine neoplasms of the appendix and colorectum]

Appropriate diagnosis and treatment of neuroendocrine neoplasms (NENs) of the appendix and colorectum requires a detailed knowledge of their proper classification according to the updated WHO and TNM systems. The WHO classification distinguishes well differentiated NEN, the neuroendocrine tumors (G1 and G2 NETs), from the poorly differentiated carcinomas (G3 NECs). While NETs are common in the appendix and rectum, NECs occur predominantly in the colon. G1 appendiceal and rectal NETs of 1 cm in size or below that do not invade either the muscular wall or vessels bear almost no metastatic risk and can be treated by appendectomy or endoscopic resection. G2 appendiceal and rectal NETs larger than 1 cm in size in combination with other risk factors have an increased risk of metastasis and need to be treated more aggressively. NECs of the colon usually require chemotherapy in addition to resection. Today, most patients with NETs of the appendix and rectum have an excellent prognosis when these diagnostic and therapeutic guidelines are borne in mind.

[Surgical strategies for accidental detection of appendix carcinoids]

Carcinoids (neuroendocrine tumors NET) of the appendix are rare tumors and even today mostly detected only postoperatively by histopathology following operations for acute appendicitis or other abdominal procedures. Most NETs of the appendix are located at the tip of the appendix, less than 2 cm in size and non-metastasizing. Secondary right hemicolectomy with lymph node dissection bears a considerable risk of complications compared to simple appendectomy. To decide upon secondary surgery histopathological risk factors, such as grading, invasion of the mesoappendix, and tumor type in addition to tumor localization and size should be taken into consideration. Up to 20% of NETs of the appendix are associated with various neoplasms of the gastrointestinal tract. Follow-up examination should therefore also consider both appendix carcinoids and synchronous or metachronous neoplasms of the gastrointestinal tract.

Mixed Adenoneuroendocrine Carcinomas (MANECs) of the Gastrointestinal Tract: An Update

The systematic application of immunohistochemical techniques to the study of tumors has led to the recognition that neuroendocrine cells occur rather frequently in exocrine neoplasms of the gut. It is now well known that there is a wide spectrum of combinations of exocrine and neuroendocrine components, ranging from adenomas or carcinomas with interspersed neuroendocrine cells at one extreme to classical neuroendocrine tumors with a focal exocrine component at the other. In addition, both exocrine and neuroendocrine components can have different morphological features ranging, for the former, from adenomas to adenocarcinomas with different degrees of differentiation and, for the latter, from well differentiated to poorly differentiated neuroendocrine tumors. However, although this range of combinations of neuroendocrine and exocrine components is frequently observed in routine practice, mixed exocrine-neuroendocrine carcinomas, now renamed as mixed adenoneuroendocrine carcinomas (MANECs), are rare; these are, by definition, neoplasms in which each component represents at least 30% of the lesion. Gastrointestinal MANECs can be stratified in different prognostic categories according to the grade of malignancy of each component. The present paper is an overview of the main clinicopathological, morphological, immunohistochemical and molecular features of this specific rare tumor type.

The role of Ki-67 in predicting biological behavior of goblet cell carcinoid tumor in appendix

BACKGROUND

The aim of this study was to examine the role of Ki-67, a cellular proliferation marker, in the prognosis of goblet cell appendiceal carcinoid tumor.

METHODS

Twelve goblet cell appendiceal carcinoid tumors were stained with MIB-1, a monoclonal antibody of Ki-67, to assess their cell proliferation and correlations with clinical and histologic parameters.

RESULTS

Among 12 patients studied, the mean MIB-1 index was 24%, with tumors ranging from .5 to 5.0 cm in size. No correlation was observed between tumor size and MIB-1 index. Two patients had metastatic disease on presentation (MIB-1 index 10% and 60%). All patients received surgical intervention according to extent of tumor invasion regardless of their MIB-1 index values. Median follow-up was 54 months, with a 75% follow-up rate and 1 death from metastasis. The overall survival rate was 76%, with a disease-specific survival rate of 87%.

CONCLUSIONS

Ki-67 had no prognostic significance for goblet cell carcinoid tumors and should not be used solely to determine treatment and surgical approach.

Metastatic Neoplasms Involving the Ovary

In this review, ovarian metastatic carcinomas from various sites, as well as other neoplasms secondarily involving the ovary, are discussed. As well as describing the morphology, the value of immunohistochemistry in distinguishing between primary and metastatic neoplasms in the ovary is discussed. While immunohistochemistry has a valuable role to play and is paramount in some cases, the results should be interpreted with caution and with regard to the clinical picture and gross and microscopic pathologic findings.

The pathological diagnosis of neuroendocrine tumors: common questions and tentative answers

Neuroendocrine neoplasms (NEN) develop in many organs, and although they share some pathological and clinical features, significant differences do exist among different tumor types and locations. The correct classification of NENs is based on the recently published WHO classification according to the various locations, and is relevant for the appropriate treatment in each group. The apparently easy diagnostic categorization in well-differentiated NENs, called neuroendocrine tumors, and poorly differentiated NENs, called neuroendocrine carcinomas, is complicated by the existence, among others, of different terminologies, morphological criteria of malignancy, combined exocrine-endocrine tumors, as well as of heterogeneous diagnostic, prognostic, and predictive markers. The present paper is an overview of the most frequently asked questions and an attempt to provide practical answers related to NEN diagnosis in the daily pathology work.

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.

Clear cell carcinoid of the appendix: an uncommon variant of lipid-rich neuroendocrine tumor with a broad differential diagnosis

The designation of clear cell/lipid-rich refers to an unusual variant of neuroendocrine tumor ("carcinoid") described in several organs, but only recently observed in the appendix. In this study, we report the morphologic, immunohistochemical, and ultrastructural features of an incidentally discovered appendiceal clear cell/lipid-rich carcinoid in a 32-year-old man without any evidence of von Hippel-Lindau disease. Differential diagnosis with mimicking neoplastic and non-tumor lesions, epidemiology, and clinical behavior of this exceedingly rare variant of carcinoid of the appendix are also discussed.

Epithelial neoplasms of the appendix

CONTEXT

The appendix gives rise to an array of epithelial neoplasms showing glandular or neuroendocrine differentiation, and some tumors with elements of both cell types. Although some appendiceal neoplasms resemble their counterparts in the small and large intestines (conventional adenocarcinoma and carcinoid tumor), the appendix also gives rise to relatively unique entities including mucinous neoplasms and goblet cell carcinoid tumors, which present a challenge in pathologic classification and clinical management.

OBJECTIVE

To review clinical and diagnostic issues for 3 pathologic types of epithelial neoplasms of the appendix: (1) adenocarcinoma, with specific focus on mucinous neoplasm; (2) goblet cell carcinoid tumor and associated adenocarcinoma; and (3) typical carcinoid tumor.

DATA SOURCES

Case-derived material and literature review.

CONCLUSIONS

The most important issue in pathologic assessment of epithelial tumors of the appendix is to understand the clinical implications inherent in the diagnosis.

Goblet cell carcinoid of the appendix: a clinicopathological and immunohistochemical study of 26 cases from southwest china

Goblet cell carcinoid (GCC) of the appendix is characterized by a dual differentiation of both endocrine and gland. This study, therefore, explores its clinicopathological and immunohistochemical features. The authors reviewed clinicopathological and immunohistochemical features of 26 GCC cases in Southwest China between 1991 and 2009. The incidence is 0.0453%, with a gender ratio of 2.71:1 (19 males and 7 females). Three cases were combined with schistosomiasis, suggesting schistosomiasis may be associated with GCC. Eighteen cases available for immunohistochemistry showed a few scattered positive cells for CD56, NSE, CgA, and Syn; diffuse positive for CEA; and preserved positive for E-cadherin and β-catenin. Follow-up data showed that 1 patient died from peritoneal metastasis and that the other 17 cases survived free of the tumor. The authors characterize GCC as a special low-grade malignant carcinoma with a primary epithelial differentiation and little neuroendocrine differentiation. A combination of both histological features and immunoreactivity is needed to diagnose GCC.

Pathology of Gastrointestinal Neuroendocrine Tumors: An Update

Gastrointestinal (GI) neuroendocrine tumors (NETs) are a heterogeneous group of relatively slow-growing neoplasms with marked site-specific differences in hormonal secretion and clinical behavior. Most are sporadic neoplasms, with only 5% to 10% arising in patients with hereditary disorders, most commonly in multiple endocrine neoplasia type 1. Although a uniform terminology is not universally accepted, use of the 4-category WHO classification of these tumors is becoming more widespread, and recommendations for tumor grading and staging have been recently formulated. Most GI NETs are easily recognized on routine histologic examination; rarely, a limited panel of immunohistochemical markers may be useful in establishing the diagnosis. This article describes general and site-specific features of these tumors and outlines potential pitfalls in diagnosis.

Nordic Guidelines 2010 for diagnosis and treatment of gastroenteropancreatic neuroendocrine tumours

The diagnostic work-up and treatment of patients with neuroendocrine tumours has undergone a major change during the last decade. New diagnostic possibilities and treatment options have been developed. These Nordic guidelines, written by a group with a major interest in the subject, summarises our current view on how to diagnose and treat these patients. The guidelines are meant to be useful in the daily practice for clinicians handling patients with neuroendocrine tumours.

The NANETS consensus guideline for the diagnosis and management of neuroendocrine tumors: well-differentiated neuroendocrine tumors of the Jejunum, Ileum, Appendix, and Cecum

Well-differentiated neuroendocrine tumors (NETs) of the jejunum, ileum, and appendix are also collectively known as midgut carcinoids. Similar to NETs in general, the diagnosed incidence of the midgut NETs is on the rise. Their presenting symptoms vary depending on stage and primary site. Local-regional NETs often present with vague and nonspecific symptoms. Classic carcinoid syndrome is more likely to appear in patients with advanced disease. Local-regional NETs of the small bowel should be resected whenever possible. With the exception of small well-differentiated NETs of the appendix, NETs of the midgut have substantial risk of relapse after resection and need to be followed for at least 7 years.Metastatic/advanced NETs of the midgut are incurable. Optimal management requires a multidisciplinary approach. Somatostatin analogs are effective in the management of carcinoid syndrome. Octreotide long-acting release has also recently been shown to delay disease progression. Liver-directed therapy and surgical debulking can improve quality of life in selected patients. Pivotal phase 3 studies with bevacizumab targeting vascular endothelial growth factor and everolimus targeting mTOR (mammalian target of rapamycin) are ongoing and may lead to improved outcome. Further studies of novel approaches such as peptide receptor radiotherapy are also warranted.

Endocrine tumors of the appendix: a pathologic review

CONTEXT

Although rare, appendiceal endocrine tumors are the most common neoplasms of the appendix. Pathologic analysis is important for guiding the management of patients.

OBJECTIVE

To provide recent data that focus on the pathology of endocrine tumors of the appendix including classifications and guidelines for patient management.

DATA SOURCES

A review of the recent literature including TNM classifications and patient management guidelines.

CONCLUSIONS

Appendiceal endocrine tumors are separated into 2 main groups: classic endocrine tumors and goblet cell carcinoids. They can be classified according to World Health Organization and TNM classifications. Evaluation of their prognoses and risks of malignancy, according to these classifications, depends on several parameters including tumor size, proliferation rate, and infiltration of appendiceal wall and mesoappendix. Most patients with classic endocrine tumors of the appendix have a favorable prognosis. Indications for postappendectomy, complementary surgery, which are still controversial, especially for tumors between 1 and 2 cm, are presented and discussed. In contrast, in patients presenting with a goblet cell carcinoid, a right hemicolectomy after the initial appendectomy is considered the standard surgical intervention.

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.

A rare case of poorly differentiated endocrine cell carcinoma of the stomach with signet ring cell differentiation

There have been few reports of the dual differentiation of different cell types within the same gastric tumor. Here, we report a rare case of poorly differentiated endocrine cell carcinoma with an associated differentiated signet ring cell population arising in the stomach. The histological appearance of the tumor by light microscopy matched the phenotype of endocrine cell carcinoma and signet ring cell differentiation with mucinous lakes. Cells with a phenotype intermediate between the two differentiated cell types were also seen in the tumor. Both the endocrine cell carcinoma and the signet ring cells were diffusely positive for chromogranin A and synaptophysin, a finding that is consistent with endocrine differentiation by immunohistochemical examination. The patient's postoperative clinical course had a poor prognosis, with aggressive tumor progression. Paraaortic lymph node recurrence was found 6 months after the operation, and the patient died of the primary disease 16 months after the surgical treatment.

Mucinous Neoplasms of the Vermiform Appendix

Most epithelial neoplasms of the vermiform appendix are of mucinous type and can be stratified into 3 main diagnostic categories: (1) adenoma, (2) mucinous neoplasms of uncertain malignant potential or low-grade mucinous neoplasm, and (3) adenocarcinoma. Clinically, appendiceal mucinous adenomas and adenocarcinomas may present as right lower abdominal pain mimicking acute appendicitis, a mass, or pseudomyxoma peritonei. Nomenclature currently in use to describe and diagnose mucinous tumors of the appendix, particularly those of low morphologic grade, varies among surgical pathologists and centers, resulting in different histologic and clinical features being attributed to these entities in the literature. It may be of help, as already attempted by some investigators, to simply apply algorithmic parameters for such lesions (grade of the primary lesion, extensiveness and composite of extra-appendiceal involvement, and so forth), instead of adopting rigid classification categories. This approach allows for more objective data to be collected in hopes that it will provide a more nuanced understanding of the clinical behavior of the spectrum of mucinous appendiceal tumors. Remaining focused on histopathologic parameters of the primary and secondary sites of involvement may help in avoiding circular reasoning.

Cervical and Endometrial Metastases of Appendiceal Goblet Cell Carcinoid

Appendiceal goblet cell carcinoid (GCC) is a rare tumor with histologic features of both adenocarcinoma and neuroendocrine tumor (carcinoid). Clinically, it behaves more aggressively than classic appendiceal carcinoid and commonly presents with peritoneal carcinomatosis. We report 2 cases of appendiceal GCC, one with uterine cervical involvement and the other with endometrial involvement as the initial presentations. The first patient's invasive cervical signet ring cell carcinoma was diagnosed on routine screening. The second patient presented with abnormal uterine bleeding, and endometrial curettage showed an adenocarcinoma with signet ring cell features. Primary appendiceal GCC was demonstrated in both cases after systematic clinical investigations. Metastatic appendiceal GCC to uterine cervix and endometrium can potentially be misinterpreted as primary cervical or endometrial signet ring cell carcinoma. Therefore, for any uterine cervical/endometrial signet ring cell carcinoma, a metastatic appendiceal GCC should be considered in the differential diagnosis, especially after excluding other primary sites.

Appendiceal neuroendocrine tumors: Recent insights and clinical implications

New insights emerged last decade that enriched our knowledge regarding the biological behavior of appendiceal neuroendocrine tumors (NETs), which range from totally benign tumors less than 1cm to goblet cell carcinomas which behave similarly to colorectal adenocarcinoma. The clinical implication of that knowledge reflected to surgical strategies which also vary from simple appendicectomy to radical abdominal procedures based on specific clinical and histological characteristics. Since the diagnosis is usually established post-appendicectomy, current recommendations focus on the early detection of: (1) the subgroup of patients who require further therapy; (2) the recurrence based on the chromogranin a plasma levels; and (3) other malignancies which are commonly developed in patients with appendiceal NETs.

Lipid-rich and clear cell neuroendocrine tumors ("carcinoids") of the appendix: potential confusion with goblet cell carcinoid

The so-called clear cell change has been described in neuroendocrine tumors at several locations. Those associated with von Hippel Lindau disease are pathognomonically "clear" and the cytoplasmic appearance has been ascribed to intracytoplasmic lipid. However, lipid has not been demonstrated in all cases of clear cell carcinoid tumors. Such variants have not been described in carcinoid tumors of the appendix and cases with a prominent proportion of clear or more correctly, lipid-rich cytoplasm may bear a superficial resemblance to goblet cell carcinoid and/or signet ring adenocarcinoma. Seven cases, in 5 females and 2 males ranging in age from 22 to 65 years, were noted to have a population of lipid-rich and vacuolated clear cells accounting for 25% or more of the tumor population. The carcinoid tumors were incidental in all cases with 4 of patients presenting with appendicitis, 2 with concomitant mucinous cystadenocarcinomas of the appendix and 1 with an adenocarcinoma of the ascending colon. Morphologically, the tumors had a nested and trabecular pattern and were composed of an admixture of microvesicular and clear lipid-rich cells. There were no mitoses, areas of necrosis of lymphovascular invasion and all cases extended to the mesoappendix. All cases were positive for synaptophysin, chromogranin, and serotonin but negative for inhibin. Three cases were examined ultrastructurally, and showed the presence of intracytoplasmic lipid and neurosecretory granules. None of the patients have shown evidence of recurrent disease. The importance of recognizing this variant of carcinoid tumor in the appendix is to avoid confusion with goblet cell carcinoid tumors with or without a signet ring adenocarcinoma. The presence of multi-vacuolated, foamy and clear cells, some resembling signet ring or goblet cells, in otherwise classic carcinoid tumors is rare but should be considered in this context in the appendix.

Diagnosis of Metastatic Neoplasms: A Clinicopathologic and Morphologic Approach

Context.—The diagnosis of the site of origin of metastatic neoplasms often poses a challenge to practicing pathologists. A variety of immunohistochemical and molecular tests have been proposed for the identification of tumor site of origin, but these methods are no substitute for careful attention to the pathologic features of tumors and their correlation with imaging findings and other clinical data. The current trend in anatomic pathology is to overly rely on immunohistochemical and molecular tests to identify the site of origin of metastatic neoplasms, but this “shotgun approach” is often costly and can result in contradictory and even erroneous conclusions about the site of origin of a metastatic neoplasm.

Objective.—To describe the use of a systematic approach to the evaluation of metastatic neoplasms.

Data Sources.—Literature review and personal experience.

Conclusions.—A systematic approach can frequently help to narrow down differential diagnoses for a patient to a few likely tumor sites of origin that can be confirmed or excluded with the use of selected immunohistochemistry and/or molecular tests. This approach involves the qualitative evaluation of the “pretest and posttest probabilities” of various diagnoses before the immunohistochemical and molecular tests are ordered. Pretest probabilities are qualitatively estimated for each individual by taking into consideration the patient's age, sex, clinical history, imaging findings, and location of the metastases. This estimate is further narrowed by qualitatively evaluating, through careful observation of a variety of gross pathology and histopathologic features, the posttest probabilities of the most likely tumor sites of origin. Multiple examples of the use of this systematic approach for the evaluation of metastatic lesions are discussed.

Goblet or signet ring cells: that is the question

Goblet cell carcinoid tumor is a rare mixed endocrine-exocrine neoplasm of the appendix. It carries an intermediate biologic behavior between a classic carcinoid tumor and a conventional adenocarcinoma. There has been a general lack of clinicopathologic parameters that can be reliably used to predict the clinical course and patient outcome. A recent retrospective study of a large number of appendiceal goblet cell carcinoids has shown that these tumors can be stratified into 3 subgroups based on careful histologic analysis: typical goblet cell carcinoid (group A); adenocarcinoma ex goblet cell carcinoid, signet ring cell type (group B); and adenocarcinoma ex goblet cell carcinoid, poorly differentiated carcinoma type (group C). Clinical follow-up data show that the histologic classification correlates with patient survival. Thus, meticulous histologic evaluation is of critical importance in determining the prognosis and guiding the management of patients with goblet cell carcinoids. This brief review summarizes these recent findings and raises a few issues that may need to be further addressed to better apply this classification to our practice.