Appendiceal Goblet Cell Carcinoid Research Articles

ASO Author Reflections: Impact of Adjuvant Chemotherapy After Right Hemicolectomy for Appendiceal Goblet Cell Carcinoid.

ASO Author Reflections: Impact of Adjuvant Chemotherapy After Right Hemicolectomy for Appendiceal Goblet Cell Carcinoid.

Molecular characterization of appendiceal goblet cell carcinoid.

231 Background: Goblet cell carcinoid (GCC) is a distinct subtype of appendiceal neoplasm that exhibits unique clinical and pathologic features. There are a few reports focusing on the molecular differences between GCC and other appendiceal tumors such as adenocarcinoma and neuroendocrine tumor (NET). Methods: A total of 495 appendiceal tumor samples (53 GCCs, 428 adenocarcinomas and 14 NETs) were tested with Next-Generation Sequencing (NGS) on a 592-gene panel and immunohistochemistry (IHC). Microsatellite instability (MSI) / mismatch repair (MMR) status was tested with a combination of NGS, IHC and fragment analysis. Tumor mutational burden (TMB) was evaluated by NGS, and PD-L1 were tested by IHC (SP142). Molecular characteristics of GCCs are compared with those of adenocarcinomas and NETs, using Chi-square test. Results: The top five genes with most frequent mutation rate in GCCs were TP53 (24.0%), ARID1A (15.4%), SMAD4 (9.4%), KRAS (7.5%) and CHEK2 (4.0%). Compared to adenocarcinomas, GCCs showed significantly lower mutation rates in KRAS (7.5% vs 60.4%), GNAS (3.8% vs 34.4%), APC (1.9% vs 11.7%), while significantly higher mutation rates in CDH1 (3.8% vs 0.7%), CHEK2 (4.0% vs 0.3%), CDC73 (2.0% vs 0.0%), ERCC2 (2.0% vs 0.0%) and FGFR2 (1.9% vs 0.0%). Compared to NETs, GCCs showed significantly lower mutation rate in KRAS (7.5% vs 28.6%), APC (1.9% vs 28.6%), BRCA2 (0.0% vs 7.1%) and FANCA (0.0% vs 7.1%), with all p < 0.05. In GCCs, MSI-H/dMMR, TML-high (> 17mut/Mb) and PD-L1 expression were seen in 0.0%, 0.0% and 2.0%, respectively. No significant difference was observed in these immune-related markers’ frequency, compared to adenocarcinomas and NETs. Conclusions: GCCs had considerably distinct mutational profile compared to appendiceal adenocarcinomas and NETs. Understanding these molecular characteristics may be critical for a development of effective treatment strategy in GCC.

Tumor-to-tumor metastasis from appendiceal adenocarcinoma to an ovarian mature teratoma, mimicking malignant transformation of a teratoma: a case report

BackgroundTumor-to-tumor metastasis (TTM) is a rare but well-documented phenomenon that is defined as metastasis in a histologically distinct tumor. Ovarian mature teratomas (OMTs) can coexist with various cancers by malignant transformation, which may make it difficult to distinguish these from TTM. Herein, we report a case of TTM from appendiceal adenocarcinoma to the OMT, mimicking the malignant transformation of OMT.Case presentationA 67-year-old Japanese woman underwent abdominal total hysterectomy and bilateral salpingo-oophorectomy for an ovarian tumor in another hospital. She was initially diagnosed with mucinous carcinoma/carcinoid arising in the OMT. One year after surgery, she was referred to our hospital after the presentation of increased appendiceal mass. Cecal biopsy targeting an appendiceal tumor revealed scattered mucinous cells with signet ring features, which were morphologically similar to the malignant components in the previously diagnosed right OMT. Both the appendiceal adenocarcinoma and malignant components of the OMT stained positive for CK7, CK20, CDX-2, and SATB2 but negative for estrogen receptor, progesterone receptor, and pax-8. Finally, we confirmed the diagnosis of appendiceal goblet cell carcinoid metastasizing to the right OMT. The patient had tumor-bearing survival due to systemic chemotherapy administered for 35 months after the initial surgery.ConclusionsAwareness of the TTM phenomenon is important to avoid an incorrect diagnosis and to select the appropriate therapy when unusual malignancy is encountered in the OMTs.

An Appendiceal Goblet Cell Carcinoid with a Low-Grade Appendiceal Mucinous Neoplasm

An Appendiceal Goblet Cell Carcinoid with a Low-Grade Appendiceal Mucinous Neoplasm

ASO Author Reflections: Outcomes of Appendiceal Goblet Cell Carcinoid Tumors.

ASO Author Reflections: Outcomes of Appendiceal Goblet Cell Carcinoid Tumors.

Goblet cell carcinoid of the appendix \u2013 diagnostic challenges and treatment updates: a case report and review of the literature

BackgroundGoblet cell carcinoid is a rare but distinct entity of appendiceal tumors which is a hybrid or mixed tumor consisting of both epithelial (glandular) and neuroendocrine elements containing goblet cells. This entity is important to recognize and appropriately grade as it tends to be more aggressive than typical carcinoid tumors, often presenting with metastatic disease. As a result, the 5-year overall survival is 14–22% in stage III–IV disease. GCC therefore warrants more aggressive surgical and medical (chemotherapy) interventions than typical carcinoid tumors. Through this case report we give a brief update on GCC pathological features, staging, surgical management, and review the literature as a guide to indications for chemotherapy and choice of agents.Case presentationWe present the case of a 77-year-old Caucasian man with a history of stage I adenocarcinoma of transverse colon status post transverse colectomy who was incidentally found on surveillance colonoscopy to have an abnormal appendiceal orifice lesion. A biopsy revealed an appendiceal goblet cell carcinoid and he underwent a right hemicolectomy which revealed a pathologic stage III GCC for which he received eight cycles of adjuvant chemotherapy with capecitabine.ConclusionsIt is essential that patients who have tumors > 2 cm, are pT3 or pT4, have higher grade histology with signet ring (Tang grade B or grade C), locally advanced, or with positive surgical margins on appendectomy undergo a right hemicolectomy. Although there is no category 1 evidence, consensus recommendations are that patients with stage II (particularly Tang B and C) and stage III GCC be offered adjuvant chemotherapy with a regimen based on 5-fluorouracil, as these patients are known to have high rates of relapse.

Histologic and Outcome Study Supports Reclassifying Appendiceal Goblet Cell Carcinoids as Goblet Cell Adenocarcinomas, and Grading and Staging Similarly to Colonic Adenocarcinomas.

Goblet cell carcinoid tumors are amphicrine tumors whose biological behavior ranges from indolent to highly aggressive, depending on tumor grade. Current grading systems for these tumors are based on identifying an adenocarcinoma arising in the setting of a goblet cell carcinoid tumor, which distinguishes this tumor from other gastrointestinal tract adenocarcinomas. Because goblet cell tumors are predominantly tumors of mucin secreting cells, we propose that they be classified as goblet cell adenocarcinomas, and graded using a methodology that has parallels in colorectal adenocarcinoma grading. We graded a large series of goblet cell adenocarcinomas by assessing the proportion of the tumor that demonstrates tubular or clustered growth. Histologic grade correlated with overall survival independent of stage, with median overall survival of 204, 86, and 29 months for low-grade, intermediate-grade, and high-grade goblet cell adenocarcinomas, respectively. Tumor stage also correlated with overall survival. We also graded the tumors according to previously proposed grading systems, and found that these systems are valid, in that they segregate patients according to prognosis.

Outcomes of Surgical and Chemotherapeutic Treatments of Goblet Cell Carcinoid Tumors of the Appendix.

Goblet cell carcinoids (GCCs) of the appendix are rare mucinous neoplasms, for which optimal therapy is poorly described. We examined prognostic clinical and treatment factors in a population-based cohort. Patients diagnosed with GCC from 1984 to 2014 were identified from the British Columbia Cancer Agency and the Vancouver Lower Mainland Pathology Archive. Of 88 cases with confirmed appendiceal GCCs, clinical data were available in 86 cases (annual population incidence: 0.66/1,000,000). Median age was 54years (range 25-91) and 42 patients (49%) were male. Metastasis at presentation was the strongest predictor of overall survival (OS), with median OS not reached for stage I-III patients, and measuring 16.2months [95% confidence interval (CI) 9.1-29] for stage IV patients. In 67 stage I-III patients, 51 (76%) underwent completion hemicolectomy and 9 (17%) received adjuvant 5-fluorouracil-based chemotherapy. No appendicitis at initial presentation and Tang B histology were the only prognostic factors, with inferior 5-year recurrence-free survival (53 vs. 83% with appendicitis, p = 0.02; 45% Tang B vs. 89% Tang A, p < 0.01). Of 19 stage IV patients, 10 (62.5%) received 5-fluorouracil-based chemotherapy and 11 (61%) underwent multiorgan resection (MOR) ± hyperthermic intraperitoneal chemotherapy (HIPEC). Low mitotic rate and MOR ± HIPEC were associated with improved 2-year OS, but only MOR ± HIPEC remained significant on multivariate analysis (hazard ratio 5.4, 95% CI 1.4-20.9; p = 0.015). In this population-based cohort, we demonstrate excellent survival outcomes in stage I-III appendiceal GCCs and clinical appendicitis. Hemicolectomy remains the standard treatment. In metastatic disease, outcomes remain poor, although MOR ± HIPEC may improve survival.

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

AbstractThe 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.

Genomic profile of appendiceal goblet cell carcinoid is distinct compared to appendiceal neuroendocrine tumor and conventional adenocarcinoma

Goblet cell carcinoid (GCC) is a rare appendiceal tumor with unique morphologic features that shows glandular and neuroendocrine differentiation on immunohistochemistry. An additional component of adenocarcinoma (AC) can be present (GCC-AC). Both GCC and GCC-AC are staged and treated like AC. The histogenesis and genetic alterations underlying GCC and GCC-AC are unclear. Capture-based next-generation DNA sequencing targeting 479 cancer genes was performed on 19 appendiceal tumors: 4 GCC, 9 GCC-AC, 3 neuroendocrine tumors (NET), and 3 AC (2 conventional, 1 mucinous). Somatic coding mutations were not seen in any NET. Pathogenic (P)/likely pathogenic (LP) mutations were present in 1 GCC, 8 GCC-AC and all 3 AC cases. P/LP mutations in chromatin remodeling genes were seen in 4 (44.4%) GCC-AC cases, but not in NET, GCC or AC. In GCC-AC, P/LP mutations in ARID1A and RHOA were each present in 3 cases, and KDM6A and SOX9 mutations were each seen in 2 cases. APC and KRAS mutations were present in 1 conventional AC case, but were not observed in any GCC or GCC-AC. This limited series reveals mutations in SOX9, RHOA, and chromatin-modifier genes in goblet cell tumors, and shows that the mutational profile of GCC/GCC-AC is distinct from NET and conventional appendiceal AC.

Severe peritoneal sclerosis after repeated pressurized intraperitoneal aerosol chemotherapy with oxaliplatin (PIPAC OX): report of two cases and literature survey

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new laparoscopic administration of chemotherapy for peritoneal metastasis (PM). PIPAC is repeated every 5th week, and seems to stabilize or improve quality of life, and might improve survival. So far, PIPAC has been well tolerated. With this paper, we aim to highlight a potential severe adverse reaction, as we describe the first cases of severe peritoneal sclerosis (SPS) caused by PIPAC. Patients with isolated PM were included in a prospective PIPAC protocol. Following insufflation of normothermic CO2, laparoscopy was performed at an intraabdominal pressure of 12mmHg. After peritoneal lavage and quadrant biopsies of the PM, the patients were treated with oxaliplatin 92mg/m2 (flowrate 0.5ml/s, maximum pressure of 200 per square inch). Treatment related toxicity was evaluated after 2weeks. Response was evaluated histologically by the Peritoneal Regression Grading Score (PRGS) and cytologically by analysis of the lavage fluid. In a series of 24 PIPAC patients treated with oxaliplatin, two patients developed SPS. Patient one had a mucinous adenocarcinoma of the appendix with PM, the mean PRGS was reduced from 2.75 to 1.75 during the course of therapy. Patient two had an appendiceal goblet cell carcinoid with a dominating mucinous adenocarcinoma component with PM, the mean PRGS was reduced from 2.00 to 1.67. Repeated applications of PIPAC with oxaliplatin can lead to SPS.

Appendiceal goblet cell carcinoid: common errors in staging and clinical interpretation with a proposal for an improved terminology

Goblet cell carcinoid (GCC) is staged and treated as adenocarcinoma (AC) and not as neuroendocrine tumor (NET) or neuroendocrine carcinoma. The term carcinoid may lead to incorrect interpretation as NET. The aim of the study was to explore pitfalls in staging and clinical interpretation of GCC and mixed GCC-AC, and propose strategies to avoid common errors. Diagnostic terminology, staging, and clinical interpretation were evaluated in 58 cases (27 GCCs, 31 mixed GCC-ACs). Opinions were collected from 23 pathologists using a survey. Clinical notes were reviewed to assess the interpretation of pathology diagnoses by oncologists. NET staging was incorrectly used for 25% of GCCs and 5% of mixed GCC-ACs. In the survey, 43% of pathologists incorrectly indicated that NET staging is applicable to GCCs, and 43% incorrectly responded that Ki-67 proliferation index is necessary for GCC grading. Two cases each of GCC and mixed GCC-AC were incorrectly interpreted as neuroendocrine neoplasms by oncologists, and platinum-based therapy was considered for 2 GCC-AC cases because of the mistaken impression of neuroendocrine carcinoma created by use of the World Health Organization 2010 term mixed adenoneuroendocrine carcinoma. The term carcinoid in GCC and use of mixed adenoneuroendocrine carcinoma for mixed GCC-AC lead to errors in staging and treatment. We propose that goblet cell carcinoid should be changed to goblet cell carcinoma, whereas GCC with AC should be referred to as mixed GCC-AC with a comment about the proportion of each component and the histologic subtype of AC. This terminology will facilitate appropriate staging and clinical management, and avoid errors in interpretation.

Perforated Goblet Cell Carcinoid Tumors of the Appendix: Navigating the Management Conundrum

Appendix is the most common site of occurrence for a goblet cell carcinoid tumor. A diagnosis of an appendiceal goblet cell carcinoid is made in retrospect the majority of the time. These tumors are best treated with a right hemicolectomy and adjuvant therapies tailored according to the presence or absence of residual disease. Presentation as a perforated appendix is seen in 16% of these tumors. The natural history and the ideal management strategy in such a scenario are not well described. In those with peritoneal spread cytoreductive surgery with HIPEC (hyperthermic intraperitoneal chemotherapy) offers the best disease-free and progression-free survival. Close follow-up with cross-sectional imaging helps in identifying recurrences at the earliest. Multimodality management involving patient participation in every aspect of care accomplishes high-value care in the treatment of these tumors.

Adenocarcinoma ex-goblet cell carcinoid (appendiceal-type crypt cell adenocarcinoma) is a morphologically distinct entity with highly aggressive behavior and frequent association with peritoneal/intra-abdominal dissemination: an analysis of 77 cases

AbstractHigh-grade versions of appendiceal goblet cell carcinoids (‘adenocarcinoma ex-goblet cell carcinoids') are poorly characterized. We herein document 77 examples. Tumors occurred predominantly in females (74%), mean age 55 years (29–84), most with disseminated abdominal (77% peritoneal, 58% gynecologic tract involvement) and stage IV (65%) disease. Many presented to gynecologic oncologists, and nine had a working diagnosis of ovarian carcinoma. Metastases to liver (n=3) and lung (n=1) were uncommon and none arose in adenomatous lesions. Tumors had various histologic patterns, in variable combinations, most of which were fairly specific, making them recognizable as appendiceal in origin, even at metastatic sites: I: Ordinary goblet cell carcinoid/crypt pattern (rounded, non-luminal acini with well-oriented goblet cells), in variable amounts in all cases. II: Poorly cohesive goblet cell pattern (diffusely infiltrative cords/single files of signet ring-like/goblet cells). III: Poorly cohesive non-mucinous cell (diffuse-infiltrative growth of non-mucinous cells). IV: Microglandular (rosette-like glandular) pattern without goblet cells. V: Mixed ‘other' carcinoma foci (including ordinary intestinal/mucinous). VI: goblet cell carcinoid pattern with high-grade morphology (marked nuclear atypia). VII: Solid sheet-like pattern punctuated by goblet cells/microglandular units. Ordinary nested/trabecular (‘carcinoid pattern') was very uncommon. In total, 33(52%) died of disease, with median overall survival 38 months and 5-year survival 32%. On multivariate analysis perineural invasion and younger age (<55) were independently associated with worse outcome while lymph-vascular invasion, stage, and nodal status trended toward, but failed to reach, statistical significance. Worse behavior in younger patients combined with female predilection and ovarian-affinity raise the possibility of hormone-assisted tumor progression. In conclusion, ‘adenocarcinoma ex-goblet cell carcinoid' is an appendix-specific, high-grade malignant neoplasm with distinctive morphology that is recognizable at metastatic sites and recapitulates crypt cells (appendiceal crypt cell adenocarcinoma). Unlike intestinal-type adenocarcinoma, it occurs predominantly in women, is disguised as gynecologic malignancy, and spreads along peritoneal surfaces with only rare hematogenous metastasis. It appears to be significantly more aggressive than appendiceal mucinous neoplasms.

Appendiceal Goblet Cell Carcinoids: Management Considerations from a Reference Peritoneal Tumour Service Centre and ENETS Centre of Excellence

Background: Appendix goblet cell carcinoids are known to share histological features of adenocarcinoma and neuroendocrine tumours. Due to their low incidence, quality evidence is lacking for the management of these patients. Methods: We performed a single-centre retrospective study of patients with a confirmed diagnosis of appendiceal goblet cell carcinoid (GCC; 1996-2014). Patients were divided into curative intent (CI) and palliative intent (PI) cohorts. Our primary end point was overall survival (OS). Results: Seventy-four patients were eligible; 76% were treated with CI [surgery only (36%), cytoreductive surgery (CRS) and hyperthermic intra-peritoneal chemotherapy (HIPEC; 36%), adjuvant chemotherapy (20%) and a combination of CRS and HIPEC followed by adjuvant chemotherapy (9%)], and 23% had advanced-stage disease amenable to palliative treatment (chemotherapy or supportive care) only. Completion right hemicolectomy, performed in 64% of the CI cohort, did not impact on the relapse rate or disease-free survival. FOLFOX chemotherapy was used in both the adjuvant and palliative settings; safety was as expected, and we observed a high rate (60%) of disease control in the palliative cohort. The estimated median OS (all patients), disease-free survival (CI patients) and progression-free survival (PI patients) were 52.1 (95% CI 29.4-90.3), 75.9 (26.6-not reached) and 5.3 (0.6-5.7) months, respectively. Age and stage were independent factors associated with OS in the multivariable analysis. Tang classification showed a trend for impact on OS. No benefit from specific adjuvant approach was identified; however, selection bias for treatment approach was observed. Conclusion: Prospective trials are needed to define optimal approaches in GCC. All GCC patients should be managed by specialized centres due to their esoteric behaviour; we provide management considerations based on our experience and conclusions.

Simplified 2-tier histologic grading system accurately predicts outcomes in goblet cell carcinoid of the appendix

Goblet cell carcinoid (GCC) is a rare appendiceal malignancy with both neuroendocrine and glandular features. Clinical outcomes of patients with GCC vary widely and a histology-based 3-tiered prognostic scheme has been previously suggested; however, this scheme is subjective and challenging to apply in day-to-day practice. We sought to construct a simplified and prognostic grading system based on objective histologic features with specific criteria. A continuous population-based cohort of GCC with clinical outcome data and archival tissue available for review was extracted from regional databases. For the 78 patients with confirmed appendiceal GCC, specific histologic features, including cytologic atypia, peritumoral stromal desmoplasia, and solid growth pattern, were recorded, and a scoring system was devised, which separates patients with GCC into low-grade (n = 55; 71%) or high-grade (n = 23; 29%) histology. Correspondingly, clinical follow-up data show good prognosis in those with low-grade histology with median and 10-year overall survival of 51.0 months and 80.5%, respectively, whereas those with high-grade histology have a poor prognosis with median and 10-year overall survival of 16.5 months (P = .006) and 0% (P < .001), respectively. Multivariate Cox proportional hazard modeling demonstrates that this 2-tier histologic system remains predictive of overall survival when controlled for TNM clinicopathological stage. These data show that a simple and objective histologic scoring system separates GCC into low- and high-grade histology with divergent clinical outcomes.

Comprehensive genomic profiling of cancer of the appendix to reveal new routes to targeted therapies.

608 Background: Cancers of the appendix are rare forms of malignancy that include two major mucin producing tumors, mucinous adenocarcinoma (MA) and goblet cell carcinoid (GCC). There is no clear standard of care for management of these malignancies. We queried whether comprehensive genomic profiling (CGP) of MA and GCC would reveal differences in the pattern of genomic alterations (GA) of these two subtypes of appendiceal cancer and serve as a guide for targeted therapies for this disease. Methods: DNA was extracted from 40 microns of FFPE sections from 20 clinically advanced appendiceal carcinomas (9 GCC and 11 MA). Comprehensive genomic profiling was performed on hybridization-captured, adaptor ligation based libraries to a high mean coverage depth of &gt;600X for 3,230 exons of 182 cancer-related genes, plus 37 introns from 14 genes frequently rearranged in cancer. The results were evaluated for all classes of GA including base substitutions, short insertions and deletions, copy number alterations and fusions/rearrangements. Clinically relevant GAs were defined as GAs linked to drugs on the market or under evaluation in mechanism driven clinical trials. Results: Base substitutions in KRAS were seen in 73% of MA and 11% of GCCs. TP53 mutations were seen in 64% of MA and 22% of GCCs. MYC (36%), SMAD4 (27%), and APC (27%) mutations were found in MA but were absent in GCC. Other GA of low frequency, but clinically relevant in both subsets included ERBB2, GNAS, ARID1A, PIK3CA, NRAS, CTNNB1, BRCA1, BRAF, KDR, PTEN, MCL1, IDH1, FBXW7, and RICTOR. Conclusions: KRAS and TP53 mutations are common in appendiceal MA, but rare in appendiceal GCCs. This confirms the differences in biology and has implications regarding the use of targeted therapies such as anti-EGFR antibody treatments. The high frequency of clinically relevant genomic alterations uncovered in this study that can potentially serve as targets for therapies, either approved or in clinical trials, raises hope that CGP can lead to improvement in outcomes for patients with this aggressive form of malignancy.

Late recurrence and metastasis of an appendiceal goblet cell carcinoid 24 years after appendectomy

Late recurrence and metastasis of an appendiceal goblet cell carcinoid 24 years after appendectomy

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

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). 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. 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). 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.

虫垂杯細胞カルチノイドを合併した虫垂憩室穿孔の1例

虫垂杯細胞カルチノイドを合併した虫垂憩室穿孔の1例