Prognostic Immunohistochemistry for Ki-67 and OTP on Small Biopsies of Pulmonary Carcinoid Tumors: Ki-67 Index Predicts Progression-free Survival and Atypical Histology.

Prognostic stratification of pulmonary carcinoids into "typical" and "atypical" categories requires examination of large tissue volume. However, there is a need for tools that provide similar prognostic information on small biopsy samples. Ki-67 and OTP immunohistochemistry have shown promising prognostic value in studies of resected pulmonary carcinoids, but prognostic value when using biopsy/cytology specimens is unclear. Ki-67 immunohistochemistry was performed on small biopsy/cytology specimens from pulmonary carcinoid tumors (n=139), and labeling index was scored via automated image analysis of at least 500 cells. OTP immunohistochemistry was performed on 70 cases with sufficient tissue and scored as positive or negative (<20% tumor nuclei staining). Higher Ki-67 index was associated with worse disease-specific progression-free survival (ds-PFS), with 3% and 4% thresholds having similarly strong associations with ds-PFS ( P <0.001, hazard ratio ≥11). Three-year ds-PFS was 98% for patients with Ki-67 <3% and 89% for patients with Ki-67≥3% ( P =0.0006). The optimal Ki-67 threshold for prediction of typical versus atypical carcinoid histology on subsequent resection was 3.21 (AUC 0.68). Negative OTP staining approached significance with atypical carcinoid histology ( P =0.06) but not with ds-PFS ( P =0.24, hazard ratio=3.45), although sample size was limited. We propose that Ki-67 immunohistochemistry may contribute to risk stratification for carcinoid tumor patients based on small biopsy samples. Identification of a 3% hot-spot Ki-67 threshold as optimal for prediction of ds-PFS is notable as a 3% Ki-67 threshold is currently used for gastrointestinal neuroendocrine tumor stratification, allowing consideration of a unified classification system across organ systems.

ETV6-NTRK2 Fusion in a Patient With Metastatic Pulmonary Atypical Carcinoid Successfully Treated With Entrectinib: A Case Report and Review of the Literature.

Pulmonary atypical carcinoid (AC) is an extremely rare neuroendocrine tumor. The neurotrophic tropomyosin receptor kinase (NTRK) fusions are reported in only 0.5% of nonsmall cell lung cancer, and are more rare in AC with only one previously reported case. Currently, there is little established evidence on the optimal therapeutic strategies and prognosis for advanced cases. We present a female patient with metastatic AC after complete resection. Due to low expression of somatostatin receptor in this case, somatostatin analogs and peptide receptor radionuclide therapy were not available. After pursuing other alternative treatments, including chemotherapy (ie, carboplatin, etoposide, capecitabine, temozolomide, and paclitaxel), everolimus, and atezolizumab, she returned with significant progression, including innumerable subcutaneous nodules, left pleura metastasis, multiple bone metastases, and brain metastases. New biopsy analysis revealed an ETV6-NTRK2 fusion. She was immediately administered the first-generation tropomyosin receptor kinase inhibitor entrectinib at a dose of 600 mg q.d. A subsequent month of treatment resulted in a complete response in all of the metastatic lung lesions. To date, she has maintained sustained benefit for at least 1 year from initiation of entrectinib. Here, we present the first case of a female patient with metastatic AC harboring the ETV6-NTRK2 fusion, and successfully treated with entrectinib, providing evidence for the application of entrectinib in patients with NTRK-positive AC, and underscoring the critical role of molecular profiling for such cases.

Advancements in medical treatment for pancreatic neuroendocrine tumors: A beacon of hope.

This editorial highlights the remarkable advancements in medical treatment strategies for pancreatic neuroendocrine tumors (pan-NETs), emphasizing tailored approaches for specific subtypes. Cytoreductive surgery and somatostatin analogs (SSAs) play pivotal roles in managing tumors, while palliative options such as molecular targeted therapy, peptide receptor radionuclide therapy, and chemotherapy are reserved for SSA-refractory patients. Gastrinomas, insulinomas, glucagonomas, carcinoid tumors and VIPomas necessitate distinct thera-peutic strategies. Understanding the genetic basis of pan-NETs and exploring immunotherapies could lead to promising avenues for future research. This review underscores the evolving landscape of pan-NET treatment, offering renewed hope and improved outcomes for patients facing this complex disease.

Pulmonary gangliocytic paraganglioma: An under-recognized mimic of carcinoid tumor.

Gangliocytic paragangliomas are rare neoplasms occurring almost exclusively in the ampullary region of the gastrointestinal tract. Although these tumors are not typically considered in the differential diagnosis of primary pulmonary neoplasia, 5 cases of primary pulmonary gangliocytic paragangliomas have been previously reported. Herein we report our experience with 3 additional examples, all referred to our Anatomic Pathology Consultation service. The patients (a 32-year-old man, a 69-year-old woman and a 55-year-old man) each presented with an endobronchial (2 cases) or upper lobe lung mass, ranging from 1.5 to 2.5 cm in maximum dimension. Biopsy and endobronchial debulking specimens demonstrated the classic triphasic morphology of gangliocytic paraganglioma, with epithelial, spindled and ganglion-like cells. By immunohistochemistry, the tumors were positive for keratin, synaptophysin and chromogranin A in the epithelial component, S100 protein and glial fibrillary acidic protein (GFAP) in the Schwannian spindled cells, and synaptophysin in ganglion cells. TTF1 expression was seen in the epithelial components of 2 cases. The Ki-67 labelling index was low (<2%). Primary pulmonary gangliocytic paragangliomas should be distinguished from carcinoid tumors, given the different natural histories and risk stratification approaches for these morphologically similar tumors. Awareness that gangliocytic paraganglioma may occur in the lung and appropriate immunohistochemical studies are key to correct diagnosis.

Gallbladder carcinoid in a cat.

Carcinoids are rare tumors that originate from neuroendocrine system cells. There has apparently only been 1 report in the veterinary medical literature of a cat with a gallbladder carcinoid, with no long-term follow-up information available from that case. Furthermore, apparently only 9 dogs with gallbladder carcinoids have been reported, again with no long-term follow-up. This case report describes the clinical presentation, surgical appearance, histopathologic and immunohistochemical findings, postoperative adjuvant chemotherapy treatment, and long-term outcome of a domestic longhair cat with a gallbladder carcinoid. The diagnosis of a gallbladder carcinoid in the present case was based on histologic and immunohistochemical findings. Clinical signs of a gallbladder carcinoid are nonspecific and ultrasonographic findings may not be definitive; however, it should be considered as a potential differential diagnosis in cats with lesions of the gallbladder or in the region of the gallbladder. The prognosis is poor, with a potentially high metastatic rate. In the present case, metastasis occurred 7 mo postoperatively despite adjuvant therapy, and the survival time was only 10 mo from the time of diagnosis. Key clinical message: This case report describes the clinical presentation, surgical appearance, histopathologic and immunohistochemical findings, postoperative adjuvant treatment, and long-term outcome of a cat with a gallbladder carcinoid, which should be considered as a potential differential diagnosis in cats with lesions of the gallbladder or in the region of the gallbladder.

Carcinoïde de la vésicule biliaire chez un chat. Les carcinoïdes sont des tumeurs rares qui prennent leur origine des cellules du système neuroendocrinien. Dans la littérature médicale vétérinaire il n'y aurait qu'un seul cas rapporté d'un chat avec un carcinoïde de la vésicule biliaire, sans aucune information de suivi à long terme disponible pour ce chat. Également, il y aurait 9 cas rapportés de chiens avec des carcinoïdes de la vésicule biliaire, mais encore là aucun suivi à long terme. Le cas présenté ici décrit la présentation clinique, l'apparence chirurgicale, les trouvailles histopathologiques et immunohistochimiques, le traitement post-opératoire par chimiothérapie adjuvante, et le devenir à long terme d'un chat domestique à poil court avec un carcinoïde de la vésicule biliaire. Dans le cas présent, le diagnostic de carcinoïde de la vésicule biliaire était basé sur les trouvailles histologiques et immunohistochimiques. Les signes cliniques d'un carcinoïde de la vésicule biliaire sont non-spécifiques et les trouvailles échographiques pourraient ne pas être concluantes; toutefois, il devrait être considéré comme un diagnostic différentiel possible chez des chats avec des lésions à la vésicule biliaire ou dans la région de la vésicule biliaire. Le pronostic est mauvais, avec un risque élevé de métastases. Dans le cas présent, des métastases sont apparues 7 mo post-chirurgie malgré une chimiothérapie adjuvante, et le temps de survie a été de 10 mo à compter du moment du diagnostic.Message clinique clé:Ce rapport de cas décrit la présentation clinique, l'apparence chirurgicale, les trouvaille histologiques et immunohistochimiques, la thérapie adjuvante postopératoire, et le résultat à long-terme pour un chat avec un carcinoïde de la vésicule biliaire, qui devrait être considéré comme un diagnostic différentiel potentiel chez les chats avec des lésions à la vésicule biliaire ou dans la région de la vésicule biliaire.(Traduit par Dr Serge Messier).

CT-based radiomics for differentiating peripherally located pulmonary sclerosing pneumocytoma from carcinoid.

BACKGROUND: Pulmonary sclerosing pneumocytoma (PSP) and pulmonary carcinoid (PC) are difficult to distinguish based on conventional imaging examinations. In recent years, radiomics has been used to discriminate benign from malignant pulmonary lesions. However, the value of radiomics based on computed tomography (CT) images to differentiate PSP from PC has not been well explored. PURPOSE: We aimed to investigate the feasibility of radiomics in the differentiation between PSP and PC. METHODS: Fifty-three PSP and fifty-five PC were retrospectively enrolled and then were randomly divided into the training and test sets. Univariate and multivariable logistic analyses were carried to select clinical predictor related to differential diagnosis of PSP and PC. A total of 1316 radiomics features were extracted from the unenhanced CT (UECT) and contrast-enhanced CT (CECT) images, respectively. The minimum redundancy maximum relevance and the least absolute shrinkage and selection operator were used to select the most significant radiomics features to construct radiomics models. The clinical predictor and radiomics features were integrated to develop combined models. Two senior radiologists independently categorized each patient into PSP or PC group based on traditional CT method. The performances of clinical, radiomics, and combined models in differentiating PSP from PC were investigated by the receiver operating characteristic (ROC) curve. The diagnostic performance was also compared between the combined models and radiologists. RESULTS: In regard to differentiating PSP from PC, the area under the curves (AUCs) of the clinical, radiomics, and combined models were 0.87, 0.96, and 0.99 in the training set UECT, and were 0.87, 0.97, and 0.98 in the training set CECT, respectively. The AUCs of the clinical, radiomics, and combined models were 0.84, 0.92, and 0.97 in the test set UECT, and were 0.84, 0.93, and 0.98 in the test set CECT, respectively. In regard to the differentiation between PSP and PC, the combined model was comparable to the radiomics model, but outperformed the clinical model and the two radiologists, whether in the test set UECT or CECT. CONCLUSIONS: Radiomics approaches show promise in distinguishing between PSP and PC. Moreover, the integration of clinical predictor (gender) has the potential to enhance the diagnostic performance even further.

Epidemiology and Prognostic Nomogram for Predicting Long-Term Disease-Specific Survival in Patients With Pancreatic Carcinoid Tumor: A SEER-Based Study.

OBJECTIVES: Pancreatic carcinoid tumor (PCT) is described as a malignant form of carcinoid tumors. However, the epidemiology and prognostic factors for PCT are poorly understood. MATERIALS AND METHODS: The data of 2447 PCT patients were included in this study from the Surveillance, Epidemiology, and End Results database and randomly divided into a training cohort (1959) and a validation cohort (488). The epidemiology of PCT was calculated, and independent prognostic factors were identified to construct a prognostic nomogram for predicting long-term disease-specific survival (DSS) among PCT patients. RESULTS: The incidence of PCT increased remarkably from 2000 to 2018. The 1-, 5-, and 10-year DSS rates were 96.4%, 90.3%, and 86.5%, respectively. Age at diagnosis, stage, surgery, radiotherapy, and chemotherapy were identified as independent prognostic factors to construct a prognostic nomogram. The C -indices; area under the receiver operating characteristic curves for predicting 1-, 5-, and 10-year DSS, and calibration plots of the nomogram in both cohorts indicated a high discriminatory accuracy, preferable survival predictive ability, and optimal concordances, respectively. CONCLUSIONS: The incidence of PCT has increased rapidly since 2000. In addition, we established a practical, effective, and accurate prognostic nomogram for predicting the long-term DSS of PCT patients.

Prognostic thresholds of fluorine-18 fluorodeoxyglucose-positron emission tomography mean and maximum standardized uptake values for survival and nodal involvement in lung neuroendocrine neoplasms.

OBJECTIVES: The mean standardized uptake value (SUVmean) and maximum standardized uptake value (SUVmax) on fluorine-18 fluorodeoxyglucose-positron emission tomography are prognostic biomarkers for survival and nodal involvement in non-small-cell lung cancer but their prognostic value in lung neuroendocrine neoplasms (NENs) remains unexplored. In this study, we aimed to examine whether they are also prognostic biomarkers for survival and nodal involvement in lung NENs. METHODS: We retrospectively studied patients with typical carcinoid, atypical carcinoid or large cell neuroendocrine carcinoma who had been radically resected at our institution between 2008 and 2020. We measured SUVmean and SUVmax on all primary tumours and lymph nodes that were clinically and/or pathologically involved. We dichotomized the patients into groups of high or low SUVmean and SUVmax of the primary tumour using time-dependent receiver operating characteristic curves and compared their overall survival using Kaplan-Meier curves and Cox models. Lastly, we predicted the patients' pathological nodal status with SUVmean and SUVmax of the lymph nodes using binomial logistic models. RESULTS: The study included 245 patients. Patients died earlier if their SUVmean of the primary tumour exceeded 3.9 [hazard ratio 1.97, 95% confidence interval (CI) 1.27-3.04, P = 0.002] or SUVmax exceeded 5.3 (hazard ratio 1.85, 95% CI 1.20-2.87, P = 0.006). Likewise, patients had a higher risk of pathological nodal involvement if their SUVmean of the lymph nodes exceeded 3.3 (odds ratio 10.00, 95% CI 2.59-51.01, P = 0.002) or SUVmax exceeded 4.2 (odds ratio 4.00, 95% CI 1.20-14.65, P = 0.028). CONCLUSIONS: The fluorine-18 fluorodeoxyglucose-positron emission tomography SUVmean and SUVmax are strong prognostic biomarkers for survival and nodal involvement in lung NENs and could be important guides for making treatment decisions.

Pulmonary Mucoepidermoid Carcinoma Mimicking Carcinoid Lung on 18 F-FDG and 68 Ga-DOTANOC PET/CT.

ABSTRACT: Pulmonary mucoepidermoid carcinoma (PMEC) is a rare pulmonary neoplasm. Although 18 F-FDG PET/CT has been shown to present with increased metabolic activity in PMEC, literature does not report increased somatostatin receptor expression in these tumors. We present the case of a 15-year-old boy where PMEC mimicked a typical carcinoid of the lung on DOTANOC PET/CT by showing significant uptake on 68 Ga-DOTANOC.

Hydrophilic molecularly imprinted resin-hexagonal boron nitride composite as a new adsorbent for selective extraction and determination of a carcinoid tumor biomarker in urine.

BACKGROUND: The detection of disease biomarkers in biological samples plays an important role in early diagnosis and treatment of carcinoid tumor. However, due to the complexity of biological samples and the extremely low concentration of disease biomarkers, sample pretreatment is still the bottleneck of achieving accurate quantitative determination. In this work, new hydrophilic molecularly imprinted resin-hexagonal boron nitride (HMIR-h-BN) composites were developed and used as a new solid phase extraction (SPE) adsorbent for selective detection of 5-hydroxyindoleacetic acid (5-HIAA), a biomarker of carcinoid tumor, in urine. RESULTS: Twenty-two types of HMIR-h-BN were successfully synthesized through growing hydrophilic molecularly imprinted resin on surface of activated two-dimensional h-BN nanosheets, and preparation parameters affecting the adsorption performance of HMIR-h-BN were investigated and optimized through adsorption experiments. HMIR-h-BN #19 (the ratio of resorcinol to hexamethylenetetramine: 6:3; the dosage of h-BN: 300 mg; the dosage of dummy template: 0.12 mmol; the imprinting time: 4 h) has demonstrated to be the optimal material for efficient separation and extraction of 5-HIAA. Combined with HPLC-UV, the limit of detection and the limit of quantification of 5-HIAA in real urine samples were 9.4 ng mL-1 and 31.3 ng mL-1, respectively, the coefficient of determination (R2) was 0.9996 in the linear range of 0.1-300 µg mL-1 and the relative recoveries ranged from 86.9 % to 97.7 % with RSD ≤5.1 %. Moreover, after being processed by HMIR-h-BN-SPE, there are no interferences from other peaks at the peak position of 5-HIAA. SIGNIFICANCE: The HMIR-h-BN composite has been demonstrated to be capable of selective extraction of 5-HIAA from urine samples and have a significant purification effect. Based on the established HMIR-h-BN-SPE-HPLC-UV method, accurate quantitative determination of 5-HIAA in urine samples was achieved, which is expected to be applied in the early diagnostic of carcinoid tumor.

Comparison of Octreotide and Vasopressors as First-Line Treatment for Intraoperative Carcinoid Crisis.

BACKGROUND: Intraoperative carcinoid crisis is typically sudden onset of profound hypotension during operations on patients with neuroendocrine tumors. The crisis was thought to be due to massive release of hormones, and perioperative octreotide was recommended as a prophylaxis against the crisis and as first-line treatment. Recent studies show that octreotide does not prevent the crisis and that no massive release of hormones occurs. Therefore, the authors hypothesized that octreotide is not effective for treating the crisis. METHODS: A prospective carcinoid anesthesia database was analyzed for occurrences of crisis. Outcomes were compared between protocols when first-line therapy was bolus octreotide and when it was vasopressors without octreotide. Significance was determined by Student's t test, the Mann-Whitney U test, and Fisher's exact test. RESULTS: Among operations performed with octreotide as first-line treatment (n = 150), crisis occurred for 45 (30 %) patients, the median crisis duration was 6 min, 12 (27 %) patients had crises longer than 10 min, 42 patients (93 %) required subsequent vasopressor administration to resolve the crisis, and 3 (2 %) operations were aborted. Among operations performed with vasopressors as the first-line treatment (n = 195), crisis occurred for 49 (25 %) patients (p = 0.31), the median crisis duration was 3 min (p < 0.001), and no crisis lasted longer than 10 min (p = 0.001). Patients treated with vasopressors were less likely to have multiple crises and had a shorter total time in crisis, a shorter anesthesia time, and no aborted operations (p < 0.05 for all). CONCLUSIONS: First-line octreotide was ineffective treatment for carcinoid crisis, with patients requiring vasopressors to resolve the crisis, and many crises lasting longer than 10 min. First-line vasopressor treatment resulted in significantly shorter crisis durations, fewer crises and aborted operations, and shorter anesthesia times. Vasopressors should be used as first-line treatment for intraoperative crisis, and treatment guidelines should be changed.

Neuroendocrine neoplasms of the ovary: a review of 63 cases.

OBJECTIVE: To describe the clinicopathological characteristics and survival outcomes of ovarian neuroendocrine neoplasms from a curated registry. METHODS: This is a retrospective cross-sectional study of patients in our registry with confirmed ovarian neuroendocrine neoplasms. We excluded patients with small cell carcinoma not otherwise specified, small cell hypercalcemic type, and those with neuroendocrine 'features' or 'differentiation.' Clinicopathological characteristics were described in two separate groups: patients with carcinoid tumors and patients with neuroendocrine carcinomas. Progression-free and overall survival were estimated with the Kaplan-Meier product-limit estimator in these two groups, and multivariable analysis was done to identify predictors of survival for neuroendocrine carcinomas only. RESULTS: A total of 63 patients met inclusion criteria, 13 (21%) with carcinoid tumors and 50 (79%) with neuroendocrine carcinomas. In the carcinoid tumor group, one patient (8%) was misdiagnosed. Two patients (15%) had a recurrence and the 5-year overall survival rate was 80% (95% CI 45% to 100%), with a lower bound of the median survival of 4.8 years (95% CI). In the neuroendocrine carcinoma group, 23 patients (46%) were misdiagnosed, 16 of whom (69%) received therapy with the presumption of a non-neuroendocrine carcinoma diagnosis. Thirty patients (60%) had a recurrence, and the 5-year overall survival rate was 24% (10%, 38%), with a median survival of 1.6 years (1.3, 3.3). Patients with carcinomas stage III or IV had an increased risk of progression/recurrence (HR=5.6; 95% CI 1.9 to 17.0) and death (HR=8.1; 95% CI 2.2 to 29.7) compared with those with stage I or II. Pure histology was associated with an increased risk of progression/recurrence (HR=2.3; 95% CI 1.0 to 5.2) compared with admixed histology. CONCLUSION: Most patients had neuroendocrine carcinomas, which were associated with a higher recurrence rate and worse survival than carcinoid tumors. A high proportion of patients in both groups were initially misdiagnosed, and a new association with endometrial hyperplasia was observed. Neuroendocrine admixed histology is associated with a higher risk of progression.

A Diagnostic Dilemma: Metastatic Neuroendocrine Tumor Mimicking Hepatocellular Carcinoma.

Carcinoid syndrome arises from neuroendocrine tumors, characterized by the presence of neurosecretory granules. The diagnosis of carcinoid syndrome involves biochemical testing and various imaging techniques. We report the case of a 62-year-old man with Parkinson's Disease who was found to have new-onset cirrhosis and multiple hepatic lesions with necrosis on CT imaging. These findings were concerning for metastatic malignancy of unknown primary origin. Subsequent MRI characterization of the liver lesions indicated hepatocellular carcinoma as the most likely diagnosis. However, a transthoracic echocardiogram, performed for anasarca and dyspnea on exertion, revealed a thickened tricuspid leaflet, highly suspicious for carcinoid valvulitis. A biopsy of one of the hepatic lesions was consistent with neuroendocrine tumor, confirming the diagnosis of carcinoid syndrome. This case highlights the limitations of diagnostic imaging approaches in distinguishing hepatocellular carcinoma from neuroendocrine tumors.

An in-silico analysis reveals further evidence of an aggressive subset of lung carcinoids sharing molecular features of high-grade neuroendocrine neoplasms.

Little is known as to whether there may be any pathogenetic link between pulmonary carcinoids and neuroendocrine carcinomas (NECs). A gene signature we previously found to cluster pulmonary carcinoids, large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC), and which encompassed MEN1, MYC, MYCL1, RICTOR, RB1, SDHA, SRC and TP53 mutations or copy number variations (CNVs), was used to reclassify an independent cohort of 54 neuroendocrine neoplasms (NENs) [31 typical carcinoids (TC), 11 atypical carcinoids (AC) and 12 SCLC], by means of transcriptome and mutation data. Unsupervised clustering analysis identified two histology-independent clusters, namely CL1 and CL2, where 17/42 (40.5%) carcinoids and all the SCLC samples fell into the latter. CL2 carcinoids affected survival adversely, were enriched in T to G transversions or T > C/C > T transitions in the context of specific mutational signatures, presented with at least 1.5-fold change (FC) increase of gene mutations including TSC2, SMARCA2, SMARCA4, ERBB4 and PTPRZ1, differed for gene expression and showed epigenetic changes in charge of MYC and MTORC1 pathways, cellular senescence, inflammation, high-plasticity cell state and immune system exhaustion. Similar results were also found in two other independent validation sets comprising 101 lung NENs (24 carcinoids, 21 SCLC and 56 LCNEC) and 30 carcinoids, respectively. We herein confirmed an unexpected sharing of molecular traits along the spectrum of lung NENs, with a subset of genomically distinct aggressive carcinoids sharing molecular features of high-grade neuroendocrine neoplasms.

Metastatic Neuroendocrine Neoplasms to the Pancreas: Two Unusual Cases and a Review of the Literature.

Neuroendocrine tumor metastases to the pancreas are rare, and they share substantial overlap with the significantly more common primary pancreatic neuroendocrine neoplasms, representing a potential diagnostic pitfall. Elucidating whether a neuroendocrine tumor within the pancreas is a primary neoplasm versus a metastasis has significant prognostic and treatment implications. Correlation with clinical history and imaging as well as incorporating an appropriate immunohistochemical panel are essential to establish the correct diagnosis. Herein, we present 2 rare neuroendocrine tumors that metastasized to the pancreas: a medullary thyroid carcinoma and an atypical carcinoid tumor of lung origin. We also provide a brief review of the literature.

A case of carcinoid syndrome probably exacerbated by hemodialysis in which prochlorperazine maleate was effective.

Carcinoid syndrome is caused by the release of serotonin and other substances, which commonly occurs due to liver metastasis of neuroendocrine tumors. It rarely occurs due to liver metastasis of neuroendocrine carcinoma. We report the case of a patient with liver metastasis of neuroendocrine carcinoma who suffered from acute abdominal pain and diarrhea triggered by hemodialysis. Various differential diagnoses were considered, but we concluded these symptoms to be probably caused by exacerbation of carcinoid syndrome, as the serum 5HIAA level was markedly elevated, and a drug with anti-serotonin activity was effective. Prochlorperazine maleate, which has anti-serotonin activity, was effective for these symptoms, and the patient was able to continue maintenance hemodialysis, which contributed to his quality of life and prognosis. We speculated the mechanism of carcinoid exacerbation was that substances such as serotonin had entered the systemic circulation via the increased extrahepatic shunt of the portal venous blood flow, entering the inferior vena cava and that this condition had been triggered by hemodialysis via the same mechanism as portal systemic encephalopathy.