Unmet Medical Needs in Pulmonary Neuroendocrine (Carcinoid) Neoplasms.

Pulmonary carcinoids (PCs) display the common features of all well-differentiated neuroendocrine neoplasms (NEN) and are classified as low- and intermediate-grade malignant tumours (i.e., typical and atypical carcinoid, respectively). There is a paucity of randomised studies dedicated to advanced PCs and management principles are drawn from the larger gastroenteropancreatic NEN experience. There is growing evidence that NEN anatomic subgroups have different biology and different responses to treatment and, therefore, should be investigated as separate entities in clinical trials. In this review, we discuss the existing evidence and limitations of tumour classification, diagnostics and staging, prognostication, and treatment in the setting of PC, with focus on unmet medical needs and directions for the future.

The use of Ki-67 labeling index to grade pulmonary well-differentiated neuroendocrine neoplasms: current best evidence.

Although Ki-67 labeling index (Ki-67%) is not a diagnostic or grading criterion in the World Health Organization classification of pulmonary carcinoid tumor, oncologists often request this test. A survey was administered at a North American Society for Neuroendocrine Tumors meeting to understand how Ki-67% is used in oncologic practices. A systematic literature review was performed to gather best evidence regarding the use of Ki-67%. Consecutive pulmonary carcinoids were stratified into pulmonary typical carcinoids with Ki-67% <5% (group A, n = 187), typical carcinoids with Ki-67% ≥5% (group B, n = 38) and atypical carcinoids irrespective of Ki-67% (group C, n = 31). Overall survival, progression-free survival, recurrence proportions and time to recurrence were compared, by group, using the log-rank test, chi-square statistics and ANOVA, respectively. Our survey confirmed that Ki-67% is frequently used by specialists caring for these patients. Ki-67% of 1-7% significantly correlated with overall survival in the literature but we found no information about Ki-67% cut-off values that would accurately distinguish pulmonary typical from atypical carcinoids or estimate the prognosis of patients stratified by World Health Organization diagnosis and Ki-67% cut-off. Overall survival was significantly different in our 3 patient groups (p < 0.001), with survival probabilities decreasing from groups A to C. Progression-free survival was significantly longer in group A than B (p < 0.007). Our results support the concept that by combining World Health Organization diagnosis and Ki-67%, pulmonary carcinoids can be stratified into 3 grades: G1 (typical carcinoids with Ki-67% <5), G2 (typical carcinoids with Ki-67% ≥5%) and G3 (atypical carcinoids) with different prognoses.

Goblet cell carcinoid of the appendix - An interobserver variability study using two proposed classification systems.

Goblet cell carcinoid (GCC) is an uncommon tumor of the vermiform appendix. Due to a broad spectrum of morphological differentiation, subclassification and grading of GCCs remains an area of controversy. Two separate systems have proposed classifying GCC tumors into three (classical GCC; adenocarcinoma ex-GCC, signet ring cell type; adenocarcinoma ex-GCC, poorly differentiated carcinoma type) OR two subgroups (low and high grade GCC) based on morphological criteria. We independently compared the inter-observer variability associated with each classification system. Overall, both systems had moderate interobserver agreement, with the two-tiered system (κ=0.54) performing slightly better than the three-tiered system (κ=0.42). GI-specialist pathologists had substantial agreement for both two and three-tiered systems (κ=0.65 vs. 0.65). Non-GI trained pathologists had lower overall agreement than GI trained pathologists, but their agreement was better using the two-tiered system (κ=0.44) than the three-tiered system (κ=0.22). A sub-analysis of 6 cases with a high rate of discordant classification revealed several challenges that exist in applying current criteria, including differentiating "goblet" vs. "signet ring" cell morphology, applying a 1 mm2 criteria to multifocal non-contiguous glandular and single infiltrating cell architecture, differentiating fibro-inflammatory stroma from desmoplastic stroma, and solid architecture in cases with abundant extracellular mucin, and distinguishing "reactive" nuclear atypia from true "cytologic atypia". Despite these challenges, the study identified better agreement among GI pathologists than non-GI trained pathologists. While GI pathologist review may be helpful, further research on objective classification criteria remains an area of interest.

Expression of hsa-let-7b-5p, hsa-let-7f-5p, and hsa-miR-222-3p and their putative targets HMGA2 and CDKN1B in typical and atypical carcinoid tumors of the lung.

Typical and atypical carcinoid tumors belong to the neuroendocrine lung tumors. They have low recurrence and proliferation rate, lymph node, and distant metastases. Nevertheless, these tumors have shown a more aggressive behavior. In the last years, microRNAs were screened as new tumor markers for their potential diagnostic and therapeutic relevance. The expression of hsa-let-7b-5p, hsa-let-7f-5p, hsa-miR-222-3p, and their targets HMGA2 (high-mobility group A2) and CDKN1B (cyclin-dependent kynase inhibitor 1B, p27kip1) was evaluated in this rare small group of patients. We analyzed the clinical data of all typical and atypical carcinoid tumors of patients who underwent surgical operation at Marburg University Hospital (n = 18) from 2000. Quantitative reverse transcription polymerase chain reaction was performed in formalin-fixed paraffin-embedded tumor tissue versus four tumor-free lung tissue samples. HMGA2 was stable or downregulated; only one patient showed a significant overexpression. CDKN1B showed a significant overexpression or a stable level; it was downregulated in two samples only. Hsa-miR-222-3p resulted almost stable or overexpressed except for two samples (significantly downregulated). Hsa-let-7f-5p was stable or overexpressed in the majority of analyzed samples, whereas hsa-let-7b-5p was significantly downregulated. HMGA2 and CDKN1B are differently expressed between atypical and typical carcinoid tumors, thus representing valid biomarkers for the classification of the two tumor groups. Hsa-let-7f-5p and HMGA2 are inversely correlated. Hsa-miR-222-3p does not correlate with its predicted target CDKN1B.

Curative Surgical Resection as a Component of Multimodality Therapy for Peritoneal Metastases from Goblet Cell Carcinoids.

BACKGROUND: The impact of histopathologic features on oncologic outcomes for patients with peritoneal metastases from goblet cell carcinoid (GCC) undergoing multimodality therapy, including cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC), is unknown. METHODS: This study prospectively analyzed 43 patients with GCC undergoing CRS-HIPEC between 2005 and 2013. Pathology slides were re-reviewed to classify GCC into histologic subtypes according to the Tang classification. Kaplan-Meier survival curves and multivariate Cox-regression models identified prognostic factors affecting oncologic outcomes. RESULTS: The 43 patients in this study underwent 50 CRS-HIPEC procedures for peritoneal metastases from GCC, and the majority received neoadjuvant and/or adjuvant systemic chemotherapy. The GCC demonstrated an aggressive phenotype with frequent lymph node and peritoneal metastases without systemic dissemination. The majority of the patients had Tang B GCC. The estimated median overall survival times after surgery for the patients with Tang A, B, and C GCC were respectively 59, 22, and 13 months. In a multivariate Cox-regression analysis, poor survival was associated with patients who had Tang B or C GCC, those undergoing incomplete macroscopic resection, and those with symptoms at the time of CRS-HIPEC. The patients with Tang A GCC demonstrated oncologic outcomes similar to those with intermediate-grade (American Joint Committee on Cancer [AJCC] grade 2) disseminated mucinous appendiceal neoplasms, whereas the patients with Tang B and C GCC demonstrated survival rates similar to or worse than those with high-grade (AJCC grade 3) disseminated mucinous appendiceal neoplasms. CONCLUSIONS: Tang classification is an independent prognostic factor for poor survival after multimodality therapy for GCC. Patients with Tang C GCC demonstrate limited survival and are not ideal candidates for a surgical approach.

[Neuroendocrine neoplasms of the mediastinum]. / Neuroendokrine Neoplasien des Mediastinums.

Primary neuroendocrine tumors (NET) in the mediastinum are very rare and among them thymic NETs are the most common. They represent 5 % of all thymic and mediastinal tumors. The WHO classification from 2015 subdivides thymic NETs into three groups; low grade (typical carcinoid), intermediate grade (atypical carcinoid) and high grade (large cell neuroendocrine carcinoma and small cell carcinoma). Through this change of mediastinal/thymic NET classification into three groups of malignancy, the nomenclature was adapted to that of the lungs, while the histological criteria for each entity remained the same. Thymic NETs typically occur in middle-aged adults and predominantly in males. Approximately 30 % are asymptomatic and the rest present with symptoms caused by local tumor growth, distant metastases and/or endocrine manifestations. Carcinoids can also occur as a part of multiple endocrine neoplasia type 1 (MEN1) and at the time of diagnosis commonly present with regional lymph node or distant metastases, which most often affect the lungs and bones. For the correct diagnosis tumor cell morphology, mitotic count and/or necrosis are crucial. Patients with typical carcinoids have the best prognosis, whereas the prognosis is slightly worse for atypical carcinoids but very poor for large cell neuroendocrine carcinomas. Small cell carcinomas have the worst prognosis and the shortest median survival time of approximately 14 months.

[Pulmonary neuroendocrine tumors and preneoplasic lesions]. / Tumeurs neuroendocrines pulmonaires et lésions prénéoplasiques.

In the recently published 2015 World Health Organization (WHO) classification of tumors of the lungs, all neuroendocrine tumors of the lungs are presented for the first time in one single chapter. In this classification, high-grade small cell lung cancer (SCLC) and large cell neuroendocrine carcinoma (LCNEC) are differentiated from intermediate grade atypical carcinoids (AC) and low-grade typical carcinoids as well as from preinvasive lesion diffuse neuroendocrine hyperplasia DIPNECH. In the 2004 WHO classification, SCLC and carcinoids each had a separate chapter and LCNEC was listed in the chapter on large cell carcinoma of the lungs. The new WHO classification also gives some recommendations for the diagnosis on small biopsies. This review describes morphological, immunohistochemical, and genomic characteristic of these tumors according to the new classification.

Identification of MicroRNAs Differentially Expressed in Lung Carcinoid Subtypes and Progression.

AIM: To extensively explore microRNA expression profiles in lung carcinoids in correlation with clinical and pathological features. METHODS: A PCR-based array was employed in the screening phase to analyze 752 microRNAs in a discovery set of 12 lung carcinoids, including 6 typical (3 with lymph node metastasis) and 6 atypical (3 with lymph node metastasis). The results were validated by means of real-time PCR in 37 carcinoids, including 22 typical (4 with lymph node metastasis) and 15 atypical (7 with lymph node metastasis), and 19 high-grade neuroendocrine carcinomas. RESULTS: Unsupervised cluster analysis segregated the pilot cases into 3 distinct groups. Twenty-four microRNAs were differentially regulated in atypical versus typical carcinoids, and 29 in metastatic versus nonmetastatic cases. Eleven microRNAs were selected for validation. All but 1 were significantly different among lung neuroendocrine tumor histotypes. Moreover, 5 (miR-129-5p, miR-409-3p, miR-409-5p, miR-185 and miR-497) were significantly upregulated in typical compared to atypical carcinoids. MiR-409-3p, miR-409-5p and miR-431-5p were also significantly downregulated in carcinoids metastatic to the lymph nodes. Predictive in silico analysis of specific target genes showed that these 3 latter microRNAs linked to metastatic potential are implicated in several cellular functions and highlighted several novel genes which may be worth exploring. CONCLUSIONS: Our findings demonstrate that lung carcinoids have distinct microRNA expression profiles as compared to high-grade neuroendocrine carcinomas and that specific microRNAs might have potential implications as diagnostic tools or clinical biomarkers.

Gastric carcinoid in the absence of atrophic body gastritis and with low Ki67 index: a clinical challenge.

BACKGROUND: Gastric carcinoids (GCs) represent 23% of all digestive neuroendocrine tumors (NETs). They can be distinguished into three types: type I (in the presence of atrophic body gastritis, ABG), type II (in the presence of Zollinger-Ellison/multiple endocrine neoplasia type I syndrome), type III (sporadic carcinoids, without any background pathology). AIM: To describe a case of undetermined type of GCs in an Italian referral center for NETs and its prevalence among GCs during a 6-year period. RESULTS: In a case series of 16 GCs seen at our unit between 2007 and 2012, 14 (83.3%) patients had type I carcinoid and 1 patient (6.2%) had type III carcinoid. One patient did not accomplish to the actual classification criteria. This patient had a well-differentiated carcinoid with low Ki67, but multiple gastric biopsies performed at 3-year follow-up gastroscopies excluded the presence of ABG. The patient had fundic cystic polyps, suggesting long-term use of proton pump inhibitors, possibly associated with GCs. CONCLUSIONS: This case shows that a GC may occur in the absence of ABG and with low Ki67 index, making classification according to actual criteria difficult. Further studies are needed to better understand the occurrence of this particular type of GCs.

Two different types of carcinoid tumors of the lung: immunohistochemical and ultrastructural investigation and their histogenetic consideration.

Carcinoid tumors have been an interesting clinical and pathological entity for pathologists because of their unique histopathologic pattern of "Zellballen" (cell ball) and the hormones they produce demonstrable by histochemical and biochemical methods, including immunohistochemistry, and the presence of cytoplasmic dense-core particles demonstrable by electron microscopy. Since carcinoid tumors were established as an entity more than a century ago by Oberndorfer, who was credited with coining the term "carcinoid," meaning carcinoma-like tumors, tumors presenting with similar characteristics have been reported in most of parenchymal organs, including lungs. Carcinoid tumors in the lungs usually occur as bronchocentric tumors and present with typical histopathologic characteristics of carcinoid tumors, but they may present with significant variation in their cellular compositions, in contrast to the midgut carcinoid tumors. In the latter, tumor cells are quite similar to enterochromaffin granule containing crypt cells, which are regarded as their progenitor cells. Currently, a similar histogenetic explanation is applied to all carcinoid tumors occurring elsewhere. The bronchus is one of the most common anatomic sites in which the carcinoid tumors occur. However, bronchial carcinoid tumors differ from the midgut counterparts in microscopic appearance, showing more variability in cellular shape and composition from the classical form of midgut carcinoid tumors. In the lungs, neuroendocrine cells (NEC) are normally found in two different ways. Firstly, they are found as randomly scattered single cells (Kultchitsky cells) similar to enteric counterparts, and, secondly, they are found in aggregates known as "neuroepithelial bodies" (NEB) usually found in the branching point of bronchi. Interestingly, they keep a close anatomic relationship with parasympathetic nerve structures and even form synapses. NEB are usually found in the early stage of fetal development and are claimed to play an important role in the branching of bronchi and regeneration of bronchial epithelial cells following tissue injury. They are claimed to play an important function as a chemoreceptor apparatus related to oxygen tension of the breathing air. To test the hypothesis that histopathologic variability found in bronchial carcinoids may be related to the fact that lungs are endowed with more than one type of NEC, the author reviewed 36 cases of bronchial carcinoids and found 8 cases in which tumor cells varied significantly from typical carcinoids in cell shape and arrangement. Tumor cells tend to be spindly with frequent presence of S-100-positive sustentacular cells. The latter was designated as type II carcinoid and the rest as type I. Ultrastructurally, tumor cells in type I exhibited features more typical for epithelial cells. The tumor cells were usually polygonal, forming closely packed cell masses, and cell membranes were closely apposed with frequent primitive cell junctions. The membrane-bound dense-core granules were of variable size and appearance and larger than those seen in type II in which the size of granules ranged from 160 to 350 nm. In 2 cases of type I, frequent cells contained myelin bodies similar to those found in type II alveolar cells. In 14 cases of type I tumors, tumor cells formed lumens into which microvilli were converging. In 5 cases, some areas showed increased cell size exceeding the usual limit of pathologist's comfortable range of small cells. In 2 cases, the tumor contained areas of adenocarcinoma. Tumor cells in type II were rather oblong and closely packed without any intercellular spaces and the majority of tumor cells contained dense-core granules typical for so-called P granules. These cells seem to give out slender cell processes containing a few dense-core granules. In rare foci, groups of thin cell processes aggregate where profiles of processes cut at different angles can be seen. In such areas one can recognize the profiles of microtubules in many of them. In one tumor, which was previously reported by the author (Ultrapath 2001;25:207), microtubule-containing dendrites were common, as seen esthesioneuroblastomas. They appeared similar to dendrites of neurons. In addition to these chief cells, there were variable numbers of agranulated cells usually found at the periphery of cell balls bordering the interstitium. Some of these cells contained large aggregates of polymorphic dense bodies. However, no definite premelanosomes were found in our series. The results indicate that there exist at least two different types of carcinoid tumors in the lungs and their immunohistochemical and ultrastructural characteristics are quite different. The type I tumors are quite similar to those found in the midgut and their histogenesis might be similar. The type II tumors showed rather definite neural features in their immunophenotypic and ultrastructural characteristics, which is difficult to explain by the same histogenesis applied to type I. We postulate that type II tumors have a different histogenesis from type I. They may derive from NEC of neuroepithelial bodies rather than Kultchitsky cells. In this regard, it is interesting to note the similarity between neuroepithelial bodies of the lungs and olfactory bulbs in their cellular composition and anatomic arrangement of epithelial cells and nerves, and the similarity between tumors they produce, bronchial carcinoid tumors in our type II and olfactory neuroblastomas. It is concluded that there are two types of bronchial carcinoid tumors having two different histogenetic pathways. Detailed analysis of the ultrastructural characteristics is the best and definite means to differentiate two types of pulmonary carcinoid tumors.

[Morphological features of pulmonary and thymic carcinoid tumor].

Morphological features of atypical and typical subtypes of pulmonary and thymic carcinoid tumors have been studied by pathohistological, immunohistochemical and electron-microscopic methods. There are the main principles of differential diagnostics in the article.

A clinical perspective on gastric neuroendocrine neoplasia.

The incidence of gastric neuroendocrine tumors (NETs) has increased exponentially based on widespread use of endoscopy and a greater pathological awareness of the condition. A key concern is the potential association with hypergastrinemia induced by proton pump inhibitor administration. Previous confusion regarding diagnosis and therapy has been diminished by a series of international consensus statements defining the biology and management strategies for the disease. Overall, gastric NETs are categorized as well-differentiated or poorly differentiated neoplasms. Well-differentiated gastric NETs are enterochromaffin-like (ECL) cell tumors subclassified into three types based on their relationship to gastrin, a key regulator of ECL cell neoplastic transformation. The treatment of type 1 and type 2 tumors depends on the size and invasiveness of the tumor, whereas type 3 tumors and poorly differentiated neuroendocrine carcinomas warrant aggressive surgical resection. The disease-specific 5-year survival ranges from about 95% in type 1 gastric carcinoids to about 25% in poorly differentiated gastric NECs. Elucidation of the precise biology of a gastric NET is critical to diagnosis and delineation of a type-specific management strategy.

[Gastric carcinoid--modern approaches to diagnosis and treatment].

Gastric carcinoid tumors are rare, but are increasing in incidence. This article reviews what is known about the classification, epidemiology, tumor pathogenesis and management of patients. Additionally we present the results of our own 10-years observation after endoscopic and surgery treatment of this tumors.

Clinical implications of lung neuroendocrine neoplasm classification.

INTRODUCTION: Neuroendocrine neoplasms of the lung (Lung NENs) encompass NE tumors (NETs), which are in turn split into typical and atypical carcinoids, and NE carcinomas (NECs), which group together small-cell carcinoma and large-cell NE carcinoma. This classification is the current basis for orienting the daily practice of these patients, with diagnostic, prognostic, and predictive inferences. AREAS COVERED: The clinical implications of lung NEN classification are addressed according to three converging perspectives, which were dissected through an extensive literature overview: (1) how to put intratumor heterogeneity into the context of the current classification; (2) how to contextualize immunohistochemistry markers to improve diagnosis, prognosis, and therapy prediction; and (3) how to use immuno-oncology strategies for life-threatening NECs, which still account for 90% or more of lung NENs. EXPERT OPINION: We provide practical insights to account for intratumor heterogeneity, practice the choice of immunohistochemistry markers, and emphasize once again the added value of immuno-oncology in the setting of personalized medicine of lung NENs.

[New TNM classification of malignant lung tumours]. / Neue TNM-Klassifikation maligner Lungentumoren.

The staging system for lung tumours is now recommended for the classification of both non-small-cell and small-cell lung cancer as well as for carcinoid tumours of the lung. The T classifications have been redefined: T1 has been subclassified as T1a (≤ 2 cm in size) and T1b (> 2-3 cm in size). T2 has been subclassified as T2a (> 3-5 cm in size) and T2b (> 5-7 cm in size). T2 (> 7 cm in size) has been reclassified as T3. Multiple tumour nodules in the same lobe have been reclassified from T4 to T3. Multiple tumour nodules in the same lung but a different lobe have been reclassified from M1 to T4. No changes have been made in the N classification. The M classification has been redefined: M1 has been subdivided into M1a and M1b. Malignant pleural and pericardial effusions have been reclassified from T4 to M1a. Separate tumour nodules in the contralateral lung have been reclassified from T4 to M1a. M1b designates distant metastasis.

[S100 protein positive sustentacular cells in pulmonary carcinoids and thoracic paragangliomas: differential diagnostic and prognostic evaluation]. / S100-Protein-positive Sustentakularzellen in pulmonalen Karzinoiden und thorakalen Paragangliomen : Differenzialdiagnostische und prognostische Bedeutung.

Paragangliomas have a classical histomorphology comprising a so-called "Zellballen" or nesting pattern with surrounding S100 protein positive sustentacular cells (SC) which form a meshwork with a wire-fence appearance. In adrenal and extra-adrenal paragangliomas the prevalence of SC is inversely associated with the patients' outcome. In order to get more insight into the prevalence as well as the prognostic and differential diagnostic value of this cell population in pulmonary carcinoids, we investigated a panel of 26 tumorlets, 147 typical and atypical pulmonary carcinoids and ten thoracic paragangliomas immunohistochemically. We were able to demonstrate that S100 protein positive cells are similarly distributed in both thoracic paragangliomas and pulmonary carcinoids. Hence, the presence and distribution of these cells does not appear to represent a reliable criterion in differential diagnosis. Moreover, all pulmonary carcinoid patients with a worse outcome had low numbers of or no S100 protein positive cells in their tissue specimens. Thus, the prevalence of these cells may potentially aid in prognostic assessment of pulmonary carcinoids, especially in biopsies.

[TNM 2010. What's new?]. / TNM 2010. Was ist neu?

In the seventh edition of the TNM Classification of Malignant Tumours there are several entirely new classifications: upper aerodigestive mucosal melanoma, gastrointestinal stromal tumour, gastrointestinal carcinoid (neuroendocrine tumour), intrahepatic cholangiocarcinoma, Merkel cell carcinoma, uterine sarcomas, and adrenal cortical carcinoma. Significant modifications concern carcinomas of the oesophagus, oesophagogastric junction, stomach, appendix, biliary tract, lung, skin, prostate and ophthalmic tumours, which will be not addressed in this article. For several tumour entities only minor changes were introduced which might be of importance in daily practice. The new classifications and changes will be commented on without going into details.

[The current TNM system for gastrointestinal tumors part II]. / Aktuelles TNM-System der gastrointestinalen Tumoren Teil II.

Entirely new classifications are those for gastrointestinal stromal tumours, gastrointestinal neuroendocrine tumours, intrahepatic cholangiocarcinoma and perihilar extrahepatic bile duct carcinomas. Major and praxis-relevant alterations concern colorectal tumours and include new classifications of carcinomas and carcinoids of the appendix. Minor alterations are seen in the classification of hepatocellular carcinomas. No changes were made for tumours of the anal canal, the gallbladder (excluding the inclusion of tumours of the cystic duct) and tumours of the pancreas and the ampulla of Vater.

Reporting lung cancer pathology specimens. Impact of the anticipated 7th Edition TNM classification based on recommendations of the IASLC Staging Committee.

Led by the International Association for the Study of Lung Cancer (IASLC), there are currently several major international collaborative projects underway that will have a significant impact on the future reporting of lung cancer pathology. In particular, the IASLC Staging Committee has just completed an analysis of >100,000 lung cancer cases, providing the basis for proposed revisions of the current TNM staging classification. The purpose of this review is not to provide a comprehensive document on recommendations for specimen processing, but rather to discuss how the anticipated changes in the 7th edition TNM will impact on specimen processing, specifically looking at tumour size, how to deal with multiple tumours and visceral pleural invasion. TNM staging of carcinoid tumours and small cell carcinoma is also 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.