EGFR, KRAS, BRAF-mutations and microsatellite instability are absent in goblet cell carcinoids of the appendix

Clinicopathological spectrums and prognosis of primary appendiceal adenocarcinoma, goblet cell adenocarcinoma, and low-grade appendiceal mucinous neoplasms

Primary appendiceal adenocarcinoma (APCA), goblet cell adenocarcinoma (GCA), and low/high-grade appendiceal mucinous neoplasms (LAMN/HAMN) are distinct entities with overlapping clinical presentation and histomorphology, leading to diagnostic challenges. We retrospectively reviewed our archived cases between 2010 and 2018 for diagnosis reappraisal and comparative analysis using updated terminology and modern parameters. A total of 87 cases (22 APCA, 40 GCA, and 25 LAMN pT≥3) were included. The entire cohort had 49 women and 38 men with a median age of 59.9 (range 26-88) years. There were no statistically significant differences in age and sex among the three groups. Clinically, patients with GCA were more likely to present with acute appendicitis (65%) and more likely to have appendectomy as initial surgery (68%). Both APCA and GCA were more likely to involve the proximal appendix while LAMN was more likely to involve the distal appendix (p<0.05). All APCAs were associated with mucosal precursor lesions, most commonly tubular, tubulovillous, or villous adenoma, flat LAMN/HAMN-pTis mucinous epithelium, or mixed, which correlated with distinct histomorphology, tumour differentiation, and stage. Although polypoid precursor lesions were rare in GCA, a significant proportion of GCA showed crypt atypia associated with neoplastic cells. Immunohistochemically, APCA had more frequent β-catenin nuclear positivity and loss of SATB2 expression (p<0.05). KRAS mutation was more common in APCA than in GCA (8/11 vs 1/7, p<0.01). We further validated the three-tiered grading system (G1, G2, G3) in GCA, which correlated well with tumour stage and patient survival. APCA had worse progression-free and disease-specific survivals than GCA and LAMN (pT≥3) with the latter being relatively indolent even when perforated with peritoneal spread. Our study is the first comprehensive comparison between all three appendiceal neoplasms. We also describe a spectrum of previously under-recognised crypt atypia in GCA, which should trigger a diligent search for GCA if present.

Clinicopathological features of appendiceal goblet cell adenocarcinoma in Japan: a multicenter retrospective study

PURPOSE

In the 5th edition of the World Health Organization classification, appendiceal goblet cell adenocarcinoma (GCA) is categorized separately from neuroendocrine tumors and other appendiceal adenocarcinomas. We clarified the clinicopathological characteristics of Japanese appendiceal GCA.

METHODS

We designed a retrospective multicenter cohort study and retrieved the data of patients with appendiceal neoplasms and histologically diagnosed appendiceal goblet cell carcinoid (GCC) treated from January 2000 to December 2017 in Japan. The available GCC slides were reviewed and diagnosed with a new grading system of GCA.

RESULTS

A total of 922 patients from 43 institutions were enrolled; of these, 32 cases were patients with GCC (3.5%), and 20 cases were ultimately analyzed. The 5-year survival rate was 61.4% (95% confidence interval: 27.4-83.2), and the median survival time was 93.1 months. For peritoneal metastasis, regional lymph node metastasis was a significant factor (p = 0.04), and Grade 3 was a potential factor (p = 0.07). No peritoneal metastasis was observed in either T1/2 patients (n = 2) or Grade 1 patients (n = 4). We were unable to detect any significant factors associated with regional lymph node metastasis.

CONCLUSION

For peritoneal metastasis, regional lymph node metastasis was a significant factor, and Grade 3 was a potential factor.

Goblet Cell Adenocarcinoma of the Appendix: A Systematic Review and Incidence and Survival of 1,225 Cases From an English Cancer Registry

Background

Goblet cell adenocarcinoma (GCA) of the appendix is a rare and aggressive tumour with varying nomenclature and classification systems. This has led to heterogeneity in published data, and there is a lack of consensus on incidence, survival, and management.

Methods

We provide an overview of GCA with a comprehensive systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology and a retrospective analysis of all cases recorded in the English National Cancer Registration and Analysis Service database between 1995 and 2018. The Kaplan–Meier estimator was used to calculate overall survival, and Cox proportional hazards regression was used to identify prognostic factors.

Results

The systematic review demonstrated an incidence of 0.05–0.3 per 100,000 per year among North American registry studies. The 1-, 3-, and 5-year survival rate was 95.5%, 85.9%–87.6%, and 76.0%–80.6%, respectively. Age, stage, and grade were identified as prognostic factors for survival. Our analysis included 1,225 cases. Age-standardised incidence was 0.0335 per year in 1995 and gradually rose to 0.158 per year in 2018. The 1-, 3-, and 5-year survival rate was 90.0% [95% confidence interval (95% CI): 85.4–94.0], 76.0% (95% CI: 73.8–80.9), and 68.6% (95% CI: 65.9–72.2), respectively. On univariate Cox regression analyses, female sex, stage, and grade were associated with worse overall survival. On multivariate analysis, only stage remained a statistically significant prognostic factor.

Conclusions

GCA of the appendix is rare, but incidence is increasing. We report a lower incidence and survival than North American registry studies. Higher stage was associated with decreased survival. Further prospective studies are required to establish optimal management.

New insights in the pathology of peritoneal surface malignancy

Pathology is central to the management of peritoneal surface malignancy. This article highlights some recent advances that have had an impact on patient management or could do so in the near future. Malignant peritoneal mesothelioma, particularly the epithelioid subtype, is amenable to radical therapy in selected cases, and factors such as ki67 proliferation index, expression of BAP1 and mutation in CDKN2A show promise as prognostic indicators. Our understanding of multicystic mesothelioma has improved in recent years; it is a true neoplasm for which surgery may be indicated. Serous carcinomas involving the peritoneum are now known to originate from tubal epithelium. They are of two distinct types, high grade and low grade, which are now recognized as different neoplasms with distinctive features, oncogenesis and behavior. Pseudomyxoma peritonei (PMP) is an unusual condition that usually arises from an appendiceal mucinous neoplasm. Recent consensus in the classification and nomenclature of these lesions is discussed, including the distinction between low grade and high grade appendiceal mucinous neoplasms (HAMN), and the diagnostic criteria for appendiceal adenocarcinoma. PMP is divided into four prognostic groups: acellular mucin, low grade mucinous carcinoma peritonei, high grade mucinous carcinoma peritonei, and high grade mucinous carcinoma peritonei with signet ring cells. The pseudomyxoma microbiome is a promising area for clinical intervention but has been the subject of little research activity. Goblet cell adenocarcinoma (previously known as 'goblet cell carcinoid') is a distinctive type of appendiceal adenocarcinoma. Its behavior correlates with histologic features, but no general consensus for classification has been reached.

Updates in Appendix Pathology: The Precarious Cutting Edge

Mucinous appendiceal tumors include low-grade appendiceal mucinous neoplasm, high-grade appendiceal mucinous neoplasm, and mucinous adenocarcinoma. Nonmucinous adenocarcinomas are less frequent. Recent consensus guidelines and the latest edition of the World Health Organization classification will allow consistent use of agreed nomenclature. Accurate diagnosis is important not only for patient management but also to allow comparison of results between centers and tumor registries. Serrated polyps are the most common benign polyp in the appendix. They need to be distinguished from low-grade appendiceal mucinous neoplasm, which can also mimic other benign conditions. Goblet cell adenocarcinomas are a distinctive type of appendiceal neoplasm.

Molecular and Genetic Markers in Appendiceal Mucinous Tumors: A Systematic Review

INTRODUCTION

The role of somatic mutation profiling in the management of appendiceal mucinous tumors (AMTs) is evolving. Using a systematic review, we identified somatic alterations (SAs) that comprise histopathologic types of AMTs and those associated with aggressive clinical phenotypes.

METHODS

MEDLINE/PubMed was searched for studies on AMTs including molecular markers or genomic alterations, published between 1990 and 2018. Studies were grouped under low- and high-grade histological type for primary and metastatic tumors.

RESULTS

Twenty-one studies involving 1099 tumors (primary/metastatic) were identified. Seven studies involving 101 primary low-grade AMTs identified KRAS (76.5%) as the predominant SA. Four studies noted GNAS in 45.2% of 42 low-grade appendiceal mucinous neoplasms, and KRAS was identified in 74.4% of 14 studies with 238 low-grade pseudomyxoma peritonei (PMP). GNAS was noted in 56% of 101 tumors and TP53 was noted in only 9.7% of 31 tumors. Primary high-grade tumors demonstrated lower SAs in KRAS (50.4% of 369 tumors) and GNAS (27.8% of 97 tumors), and higher SAs in TP53 (26.0% of 123 tumors). In high-grade PMP, SAs were noted in KRAS (55.0% of 200 tumors), GNAS (35.0% of 60 tumors), and TP53 (26.3% of 19 tumors). No clear association was noted between SAs and survival.

CONCLUSIONS

KRAS and GNAS are frequently altered in low-grade AMTs, while TP53 is frequently altered in high-grade AMTs, with no apparent change in expression between primary and metastatic tumors. Although SAs may provide valuable insights into variability in tumor biology, larger studies utilizing clinically annotated genomic databases from multi-institutional consortiums are needed to improve their identification and clinical applicability.

Goblet cell tumors of the appendix: A review

Goblet cell tumors are rare tumors of the appendix that exhibit both neuroendocrine and mucinous differentiation. This dual differentiation has led to a controversy regarding the proper classification of these neoplasms as to whether they should be considered neuroendocrine tumors or adenocarcinomas. Multiple grading systems have been proposed that were able to segregate these tumors into prognostically significant groups. Many of these grading systems rely on identifying and/or quantifying the carcinomatous growth pattern. Goblet cell tumors show patchy and focal expression of neuroendocrine markers and are characterized by a mutational profile that is different from both appendiceal adenocarcinomas and neuroendocrine tumors. They exhibit a more aggressive behavior than neuroendocrine tumors, and as such, many authors recommend that they be approached and treated as adenocarcinomas.

Genetics and Epigenetics of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are heterogeneous regarding site of origin, biological behavior, and malignant potential. There has been a rapid increase in data publication during the last 10 years, mainly driven by high-throughput studies on pancreatic and small intestinal neuroendocrine tumors (NETs). This review summarizes the present knowledge on genetic and epigenetic alterations. We integrated the available information from each compartment to give a pathway-based overview. This provided a summary of the critical alterations sustaining neoplastic cells. It also highlighted similarities and differences across anatomical locations and points that need further investigation. GEP-NENs include well-differentiated NETs and poorly differentiated neuroendocrine carcinomas (NECs). NENs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, NECs are G3 by definition. The distinction between NETs and NECs is also linked to their genetic background, as TP53 and RB1 inactivation in NECs set them apart from NETs. A large number of genetic and epigenetic alterations have been reported. Recurrent changes have been traced back to a reduced number of core pathways, including DNA damage repair, cell cycle regulation, and phosphatidylinositol 3-kinase/mammalian target of rapamycin signaling. In pancreatic tumors, chromatin remodeling/histone methylation and telomere alteration are also affected. However, also owing to the paucity of disease models, further research is necessary to fully integrate and functionalize data on deregulated pathways to recapitulate the large heterogeneity of behaviors displayed by these tumors. This is expected to impact diagnostics, prognostic stratification, and planning of personalized therapy.

Goblet Cell Carcinoid/Carcinoma: An Update

Goblet cell carcinoid (GCC) or goblet cell carcinoma is a unique mixed endocrine-exocrine neoplasm that is almost exclusively seen in the appendix. The hallmark of GCC is the concentric infiltration of the appendiceal wall by small tight clusters, nests or cords of tumor cells that exhibit a goblet cell morphology with a small compressed nucleus and conspicuous intracytoplasmic mucin. The coexistence of high-grade adenocarcinoma with GCC has been increasingly recognized as a common finding, which has been called adenocarcinoma ex GCC or mixed GCC-adenocarcinoma. A number of studies have shown that it is the high-grade adenocarcinomatous component that dictates the prognosis. Several histologic classification/grading systems have been proposed, which correlate with overall patient survival. Treatment options are primarily based on tumor stage and the presence or absence of a high-grade adenocarcinomatous component.

Molecular Diagnostics in the Neoplasms of Small Intestine and Appendix: 2018 Update

Neoplasms of the small intestine are rare in comparison with colorectal tumors. The most common tumor types arising in the small intestine are adenocarcinomas, well-differentiated neuroendocrine tumors, gastrointestinal stromal tumors, and lymphoma. Primary appendiceal neoplasms are rare and found in less than 2% of appendectomy specimens with an incidence of approximately 1.2 cases per 100,000 people per year in the United States. This article explores molecular diagnostics in the neoplasms of small intestine and appendix.

SATB2 Shows Different Profiles Between Appendiceal Adenocarcinomas Ex Goblet Cell Carcinoids and Appendiceal/Colorectal Conventional Adenocarcinomas: An Immunohistochemical Study With Comparison to CDX2

Background

Special AT-rich sequence-binding protein 2 (SATB2) is a novel marker for colorectal adenocarcinomas but little is known about its expression in appendiceal adenocarcinomas. We aim to investigate SATB2 in these tumors and colorectal adenocarcinomas with comparison to CDX2.

Methods

Immunohistochemical stains for SATB2 and CDX2 were performed in 49 appendiceal adenocarcinomas (23 conventional, 26 adenocarcinoma ex goblet cell carcinoids (AdexGCCs)) and 57 colorectal adenocarcinomas. Their expression was correlated with tumor differentiation and growth patterns.

Results

SATB2 staining was positive in 26/26 (100%) appendiceal AdexGCCs and 15/23 (65%) appendiceal conventional adenocarcinomas (P = 0.001). Their mean percentage of SATB2-positive cells was 93% and 34%, respectively (P < 0.0001). CDX2 staining was seen in 26/26 (100%) AdexGCCs and 22/23 (96%) appendiceal conventional adenocarcinomas (P = 0.4694). SATB2 and CDX2 showed similar staining in AdexGCCs but CDX2 labeled more tumor cells than SATB2 in conventional adenocarcinomas (mean 84% vs. 34%, P < 0.0001). SATB2 and CDX2 staining was seen in 82% (47/57) and 96% (55/57) colorectal adenocarcinomas, respectively (P = 0.01). The mean percentage of cells positive for SATB2 and CDX2 was 48% and 91%, respectively (P < 0.00001). Decreased SATB2 immunoreactivity was associated with non-glandular differentiation particularly signet ring cells in colorectal (P = 0.001) and appendiceal conventional adenocarcinomas (P = 0.04) but not in appendiceal AdexGCCs.

Conclusions

SATB2 is a highly sensitive marker for appendiceal AdexGCCs with similar sensitivity as CDX2. In colorectal and appendiceal conventional adenocarcinomas, SATB2 is not as sensitive as CDX2 and its immunoreactivity is dependent on tumor differentiation.

Appendiceal goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid are genetically distinct from primary colorectal-type adenocarcinoma of the appendix

The appendix gives rise to goblet cell carcinoids, which represent special carcinomas with distinct biological and histological features. Their genetic background and molecular relationship to colorectal adenocarcinoma is largely unknown. We therefore performed a next-generation sequencing analysis of 25 appendiceal carcinomas including 11 goblet cell carcinoids, 7 adenocarcinomas ex-goblet cell carcinoid, and 7 primary colorectal-type adenocarcinomas, using a modified Colorectal Cancer specific Panel comprising 32 genes linked to colorectal and neuroendocrine tumorigenesis. The mutational profiles of these neoplasms were compared with those of conventional adenocarcinomas, mixed adenoneuroendocrine carcinomas, and neuroendocrine carcinomas of the colorectum. In addition, a large-scale pan-cancer sequencing panel covering 409 genes was applied to selected cases of goblet cell carcinoid/adenocarcinoma ex-goblet cell carcinoid (n=2, respectively). Mutations in colorectal cancer-related genes (eg, TP53, KRAS, APC) were rare to absent in both, goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid, but frequent in primary colorectal-type adenocarcinomas of the appendix. Additional large-scale sequencing of selected goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid revealed mutations in Wnt-signaling-associated genes (USP9X, NOTCH1, CTNNA1, CTNNB1, TRRAP). These data suggest that appendiceal goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid constitute a morphomolecular entity, histologically and genetically distinct from appendiceal colorectal-type adenocarcinomas and its colorectal counterparts. Altered Wnt-signaling associated genes, apart from APC, may act as potential drivers of these neoplasms. The absence of KRAS/NRAS mutations might render some of these tumors eligible for anti-EGFR directed therapy regimens.

Molecular analysis of BRAF V600E mutation in multiple nodules of pulmonary Langerhans cell histiocytosis

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare, smoking-related histiocytic disorder with variable clinical symptoms. Like in other non-pulmonary Langerhans cell proliferations, PLCH has recently been shown to harbour BRAF V600E mutations in a significant subset of cases, thus challenging the concept of PLCH being a reactive disorder. Here, we analysed 38 formalin-fixed and paraffin-embedded PLCH nodules of nine patients for BRAF mutation using two different molecular methods. Using pyrosequencing and allele-specific quantitative PCR (AS-PCR), BRAF V600E mutations were found in 16/38 (42%) and 31/37 (84%) nodules, respectively. Analysing different nodules of the same patients with pyrosequencing 3/6 patients showed a concordant BRAF mutation status. When allele-specific quantitative PCR was used, condordant results were found in 5/6 patients. Our findings clearly indicate that (a) the sensitivity of the method used is crucial in analysing BRAF mutation status, (b) AS-PCR is more sensitive in detecting BRAF V600E mutations than pyrosequencing,

Predictive factors of response to mTOR inhibitors in neuroendocrine tumours

Medical treatment of neuroendocrine tumours (NETs) has drawn a lot of attention due to the recent demonstration of efficacy of several drugs on progression-free survival, including somatostatin analogs, small tyrosine kinase inhibitors and mTOR inhibitors (or rapalogs). The latter are approved as therapeutic agents in advanced pancreatic NETs and have been demonstrated to be effective in different types of NETs, with variable efficacy due to the development of resistance to treatment. Early detection of patients that may benefit from rapalogs treatment is of paramount importance in order to select the better treatment and avoid ineffective and expensive treatments. Predictive markers for therapeutic response are under intensive investigation, aiming at a tailored patient management and more appropriate resource utilization. This review summarizes the available data on the tissue, circulating and imaging markers that are potentially predictive of rapalog efficacy in NETs.

Appendiceal Neuroendocrine, Goblet and Signet-Ring Cell Tumors: A Spectrum of Diseases with Different Patterns of Presentation and Outcome

PURPOSE

Appendiceal tumors are a heterogeneous group of diseases that include typical neuroendocrine tumors (TNET), goblet cell carcinoids (GCC), and atypical GCC. Atypical GCC are classified into signet-ring cell cancers (SRCC) and poorly differentiated appendiceal adenocarcinoids. The prognosis and management of these diseases is unclear because there are no prospective studies. The aim of this study is to assess the characteristics and outcome of appendiceal TNET, GCC, and SRCC patients.

MATERIALS AND METHODS

Appendiceal TNET, GCC, and SRCC patients diagnosed between 1973 and 2011 were identified in the Surveillance Epidemiology and End Results (SEER) database. Demographics, type of surgery, and clinicopathologic characteristics were collected. Survival functions were estimated by the Kaplan-Meier method, and log-rank test was used to assess the difference in overall survival (OS) among the three histologies.

RESULTS

The SEER database yielded 1,021 TNET patients, 1,582 with GCC, and 534 SRCC patients. TNET presented at a younger age (p < 0.001). Patients with SRCC presented with advanced stage disease (p < 0.001). The median OS (mOS) for GCC and TNET patients was not reached; mOS for SRCC was 24 months. Multivariate analysis stratified for stage revealed significantly longer survival for TNET and GCC than SRCC (p < 0.001).

CONCLUSION

This is the largest report to date for appendiceal neuroendocrine tumor patients, suggesting a spectrum of diseases with different characteristics and outcomes. In this report, we present a treatment approach for this complex spectrum of disease, based on the experience of Ohio State and Emory Universities investigators.

Molecular Profiling of Appendiceal Epithelial Tumors Using Massively Parallel Sequencing to Identify Somatic Mutations

BACKGROUND

Some epithelial neoplasms of the appendix, including low-grade appendiceal mucinous neoplasm and adenocarcinoma, can result in pseudomyxoma peritonei (PMP). Little is known about the mutational spectra of these tumor types and whether mutations may be of clinical significance with respect to therapeutic selection. In this study, we identified somatic mutations using the Ion Torrent AmpliSeq Cancer Hotspot Panel v2.

METHODS

Specimens consisted of 3 nonneoplastic retention cysts/mucocele, 15 low-grade mucinous neoplasms (LAMNs), 8 low-grade/well-differentiated mucinous adenocarcinomas with pseudomyxoma peritonei, and 12 adenocarcinomas with/without goblet cell/signet ring cell features. Barcoded libraries were prepared from up to 10 ng of extracted DNA and multiplexed on single 318 chips for sequencing. Data analysis was performed using Golden Helix SVS. Variants that remained after the analysis pipeline were individually interrogated using the Integrative Genomics Viewer.

RESULTS

A single Janus kinase 3 (JAK3) mutation was detected in the mucocele group. Eight mutations were identified in the V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and GNAS complex locus (GNAS) genes among LAMN samples. Additional gene mutations were identified in the AKT1 (v-akt murine thymoma viral oncogene homolog 1), APC (adenomatous polyposis coli), JAK3, MET (met proto-oncogene), phosphatidylinositol-4,5-bisphosphate 3-kinase (PIK3CA), RB1 (retinoblastoma 1), STK11 (serine/threonine kinase 11), and tumor protein p53 (TP53) genes. Among the PMPs, 6 mutations were detected in the KRAS gene and also in the GNAS, TP53, and RB1 genes. Appendiceal cancers showed mutations in the APC, ATM (ataxia telangiectasia mutated), KRAS, IDH1 [isocitrate dehydrogenase 1 (NADP+)], NRAS [neuroblastoma RAS viral (v-ras) oncogene homolog], PIK3CA, SMAD4 (SMAD family member 4), and TP53 genes.

CONCLUSIONS

Our results suggest molecular heterogeneity among epithelial tumors of the appendix. Next generation sequencing efforts have identified mutational spectra in several subtypes of these tumors that may suggest a phenotypic heterogeneity showing mutations that are relevant for targeted therapies.