Carcinoid Research Articles

S4111 A Case Series of Threes: Three Gastrointestinal Carcinoid Tumors in Three Locations Treated With Three Novel Endoscopic Techniques

S4111 A Case Series of Threes: Three Gastrointestinal Carcinoid Tumors in Three Locations Treated With Three Novel Endoscopic Techniques

S389 Active Ulcerative Colitis and Rectal Carcinoid Tumors: A Rare Occurrence

S389 Active Ulcerative Colitis and Rectal Carcinoid Tumors: A Rare Occurrence

Laccase mimetics as sensing elements for amperometric assay of 5-hydroxyindoleacetic acid in urine

Monitoring of the levels of 5-hydroxyindole-3-acetic acid (5-HIAA) is of significant importance for diagnostics of carcinoid tumors. We propose simple catalytic electrochemical sensors for the determination of 5-HIAA in urine using laccase and its mimetics. Laccase-like nanozymes (LacNZs) were synthesized via a chemical reduction, and resulting PtMn and MnO2 nanoflowers (NFs) demonstrated laccase-like activity similar to the laccase from the Trametes zonata. In addition, these LacNZs showed enhanced stability under a wide range of pH (3.0–7.5), temperatures (4–70 °C), and ionic strengths (up to 500 mM NaCl). The developed PtMn NF/graphite electrode, similar to a laccase/graphite electrode, can detect 5-HIAA with a high sensitivity (25 000 ± 12 A·M−1·m−2 and 1900 ± 9 A·M−1·m−2, respectively) and have linear ranges of 0.3 – 15 μM and 2 – 50 μM. The sensors work at low working potentials with a detection limit of 0.16 and 1.4 μM, covering the normal and pathologic ranges of 5-HIAA (1–50 μM) content in urine. They have been successfully applied to 5-HIAA assay in urine samples of people with various diseases and revealed good recovery values and reproducibility. Additionally, the LacNZ-sensor has the best stability and can be used up to 20 days.

Incidence trends of gastric cancer in the United States over 2000-2020: A population-based analysis.

Gastric cancer ranks among the top cancers in terms of both occurrence and death rates in the United States (US). Our objective was to provide the incidence trends of gastric cancer in the US from 2000 to 2020 by age, sex, histology, and race/ethnicity, and to evaluate the effects of the COVID-19 pandemic. We obtained data from the Surveillance, Epidemiology, and End Results 22 program. The morphologies of gastric cancer were classified as adenocarcinoma, gastrointestinal stromal tumor, signet ring cell carcinoma, and carcinoid tumor. We used average annual percent change (AAPC) and compared pairs using parallelism and coincidence. The numbers were displayed as both counts and age-standardized incidence rates (ASIRs) per 100000 individuals, along with their corresponding 95% confidence intervals (CIs). Over 2000-2019, most gastric cancers were among those aged ≥55 years (81.82%), men (60.37%), and Non-Hispanic Whites (62.60%). By histology, adenocarcinoma had the highest incident cases. During the COVID-19 pandemic, there was a remarkable decline in ASIRs of gastric cancer in both sexes and all races (AAPC: -8.92; 95% CI: -11.18 to -6.67). The overall incidence trends of gastric cancer were not parallel, nor identical. The incidence of gastric cancer shows notable variations by age, race, and sex, with a rising trend across ethnicities. While the overall incidence has declined, a noteworthy increase has been observed among younger adults, particularly young Hispanic women; however, rates decreased significantly in 2020.

Metabolomic Profiling of Pulmonary Neuroendocrine Neoplasms.

Pulmonary neuroendocrine neoplasms (NENs) account for 20% of malignant lung tumors. Their management is challenging due to their diverse clinical features and aggressive nature. Currently, metabolomics offers a range of potential cancer biomarkers for diagnosis, monitoring tumor progression, and assessing therapeutic response. However, a specific metabolomic profile for early diagnosis of lung NENs has yet to be identified. This study aims to identify specific metabolomic profiles that can serve as biomarkers for early diagnosis of lung NENs. We measured 153 metabolites using liquid chromatography combined with mass spectrometry (LC-MS) in the plasma of 120 NEN patients and compared them with those of 71 healthy individuals. Additionally, we compared these profiles with those of 466 patients with non-small-cell lung cancers (NSCLCs) to ensure clinical relevance. We identified 21 metabolites with consistently altered plasma concentrations in NENs. Compared to healthy controls, 18 metabolites were specific to carcinoid tumors, 5 to small-cell lung carcinomas (SCLCs), and 10 to large-cell neuroendocrine carcinomas (LCNECs). These findings revealed alterations in various metabolic pathways, such as fatty acid biosynthesis and beta-oxidation, the Warburg effect, and the citric acid cycle. Our study identified biomarker metabolites in the plasma of patients with each subtype of lung NENs and demonstrated significant alterations in several metabolic pathways. These metabolomic profiles could potentially serve as biomarkers for early diagnosis and better management of lung NENs.

Ratiometric surface-enhanced Raman spectroscopy detection of 5-hydroxyindole-3-acetic acid based on Au@MIL-125@MIPs substrates

5-Hydroxyindole-3-acetic acid (5-HIAA) is a molecular marker that can be used in the early diagnosis of carcinoid tumors, and the development of sophisticated 5-HIAA assays is therefore of great importance. Surface-enhanced Raman spectroscopy (SERS) has been widely used for the rapid and sensitive detection of disease biomarkers. Insufficient specificity for tumor markers and poor spectral reproducibility are the bottlenecks in the practical use of SERS technology. In this study, based on MIL-125 surface-loaded gold nanoparticles (Au@MIL-125), a novel strategy was proposed to obtain Au@MIL-125@molecularly imprinted polymers (MIPs) as functional SERS substrates by wrapping a thin MIP shell around the Au@MIL-125 surface for selective separation followed by a 5-HIAA assay. The Raman peak intensity ratio (I865/I1078) was used to quantify 5-HIAA after a SERS spectral calibration with an embedded internal standard (i.e., 4-aminobenzenethiol) to improve the quantitative accuracy. The linear range was from 10−11 to 10−7 M, and the limit of detection (LOD) was 5.45 × 10−13 M. The method of integrating the MIPs with the metal MOF-based nanocomposites was shown to be useful in the analysis of real samples using SERS. The application of SERS for the selective and quantitative detection of analytes in real sample analysis, therefore, has great potential.

EP142 - "Unravelling the Enigma: Navigating the Diagnostic Dilemma of Abdominal Toxoplasmosis"

Abstract Introduction Abdominal toxoplasmosis, an infrequent yet medically significant manifestation of Toxoplasma infection, primarily caused by the protozoan parasite Toxoplasma gondii. Although toxoplasmosis can affect various organs, its occurrence in the abdominal region introduces unique diagnostic complexities, presenting symptoms such as abdominal pain, gastrointestinal disruptions, and systemic complications. Case Report In a notable case, a middle-aged patient presented with perplexing gastrointestinal symptoms, including nausea, vomiting, abdominal pain, and irregular bowel habits. With a history of anaemia and thrombocytopenia necessitating transfusions and yielding inconclusive bone marrow biopsies, the patient underwent OGD and colonoscopy with biopsies during initial management, revealing a hiatus hernia and diverticulosis that did not explain the symptoms. Despite being discharged pending biopsy results, subsequent normal findings failed to clarify. Upon readmission with persistent gastrointestinal complaints, a CTAP revealed two suspicious neoplastic focal areas of small bowel wall thickening and enlarged mesenteric lymph nodes. The MDT discussions ensued to rule out malignancy, leading to a follow-up PET scan suggesting nodal disease, raising concerns about lymphoma, small bowel adenocarcinoma, or carcinoid tumour and recommended an ultrasound-guided lymph node biopsy, 5 HIAA if asymptomatic, and diagnostic laparoscopy if symptomatic or obstructed. Subsequent core biopsy of a neck lymph node unveiled appearances consistent with toxoplasmosis, prompting treatment with anti-parasitic drugs. The patient awaits capsule endoscopy, and a follow-up CT scan displayed a reduction in bowel lesions and lymph nodes. Conclusion This case highlights the swift and precise identification of toxoplasmosis, resulting in an optimal patient outcome. The clinical manifestations of toxoplasmosis are diverse and lack distinct characteristics, making it challenging to definitively diagnose, particularly in immunocompetent individuals.

18F-FDG, 68Ga-PSMA, and 64Cu-DOTATATE PET/CT—One Patient, Three Cancers

Abstract A 67-year-old man with a history of multiple myeloma, prostate cancer, and rectal carcinoid tumor underwent 18F-FDG PET/CT for surveillance, which revealed a non–FDG-avid lesion in the liver. To rule out metastasis from prostate cancer and carcinoid tumor, 68Ga-PSMA and 64Cu-DOTATATE PET/CT scans were ordered for respective malignancies. The 64Cu-DOTATATE scan showed radiotracer uptake in the hepatic lesion compatible with metastasis of the carcinoid tumor. Additionally, both 68Ga-PSMA and 64Cu-DOTATATE PET/CT scans revealed nodal metastasis within the pelvis. This case highlights the importance of appropriate radiotracer selection in conjunction with patient history in the evaluation of patients with multiple malignancies.

The role of wedge resection and lymph node examination in stage IA lung carcinoid tumors.

Current guidelines recommend anatomical resection and mediastinal lymph node resection for stage I to IIIA pulmonary carcinoids (PCs). The role of wedge resection in stage IA PCs remains controversial, previous studies focused on typical carcinoids (TCs) while differentiating histological subtypes preoperatively is not easy. We aimed to study the effect of wedge resection and lymph node examination (LNE) in patients with stage IA PCs. Patients who underwent anatomical and wedge resection for stage T1N0M0 lung carcinoid tumors between 2004 and 2019 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were also divided into a non-LNE group and an LNE group. Kaplan-Meier analysis and the log-rank test were used to calculate and compare overall survival (OS). Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to balance the variables between groups. Univariate and multivariate Cox proportional hazard models were developed to determine prognostic factors. A total of 2,029 patients with bronchopulmonary carcinoid tumors were included in this study, 1,450 underwent lobectomy, 147 underwent segmentectomy and 432 underwent wedge resection. Initially, 5-year survival differed marginally between wedge and anatomical resection (91% vs. 95%, P=0.051), but lost significance after adjustment. LNE improved 5-year survival (95% vs. 89%, P=0.003), and this remained significant after adjustment. In multivariate cox analysis, LNE remained a significant variable while extent of resection was not. This result also remained consistent after adjustment. OS was comparable between wedge resection and anatomical resection when at least 1 lymph node was examined. For early-stage PC, wedge resection was not inferior to anatomical resection in terms of OS, while LNE significantly increased the survival in both multivariate and matched studies. The relationship between surgical extent and survival in the unadjusted study may be attributed to the lower rate of LNE in wedge resection. Our findings support wedge resection with emphasis on LNE in early-stage PCs.

Carcinoid Tumor of the Lung: An Audit of Small Specimen Reports and Correlation with Resection

Carcinoid Tumor of the Lung: An Audit of Small Specimen Reports and Correlation with Resection

Pneumomediastinum as a manifestation of a bronchial carcinoid tumour: a very rare association of two uncommon diseases

A 29-year-old man presented to the emergency department with haemoptysis and thoracic pain. His vital signs and blood tests were normal, except for increased C-reactive protein levels. Fibrolaryngoscopy and esophagogastroduodenoscopy results were negative. Computed Tomography of the chest revealed abundant pneumomediastinum, air dissection along the peribronchovascular sheaths of the left lower lobe and a vegetating lesion completely occluding the distal extremity of the left main bronchus. After complete bronchoscopic excision of the lesion, histological examination revealed a carcinoid tumour not otherwise specified. After hospital discharge, 18F-fluorodeoxyglucose and 68Ga-DOTANOC positron emission tomographies ruled out distant metastases. A sleeve resection of approximately 20 mm of the distal extremity of the left main bronchus and a circumferential anastomosis between the left main bronchus and ipsilateral lobar bronchi were performed. Several bronchoscopic follow-ups did not show anastomotic dehiscence or tumour relapse.

Management of carcinoid heart disease

Carcinoid Heart Disease (CaHD) is defined as the constellation of all cardiac manifestations that occur in patients with carcinoid tumors. Cardiac manifestations are generally due to the paraneoplastic effects of vasoactive substances secreted by carcinoid tumors. These primarily cause cardiac valve dysfunction and resultant heart failure. Successful management of patients with CaHD requires a multidisciplinary team to address both the classical manifestations of carcinoid syndrome, as well as the additional manifestations of cardiac dysfunction. While the cornerstone of medical management for carcinoid syndrome are somatostatin analogs (SSAs), there is no evidence to suggest that the usage of SSAs influences the development or progression of CaHD. Additionally, while liver-directed therapies provide a survival benefit to symptomatic carcinoid syndrome patients with resectable disease, there are conflicting data on the survival benefit of hepatic resection among patients with CaHD. Cardiac surgery in patients with CaHD is a complex undertaking, and is the only definitive treatment for symptom management in CaHD with significant survival benefit for patients in advanced disease states. Two crucial surgical decisions to be made are determining which valve(s) should be replaced, and what prosthetic should be utilized. While challenging in this often medically frail population, cardiac surgery confers a survival benefit and should be pursued in cases of symptomatic CaHD or progressive right ventricular dysfunction.

An aggressive Cushing's syndrome originating from a rare thymic neuroendocrine tumor, controlled successfully with fluconazole and octreotide therapy before surgery.

Cushing's syndromes (CSs) due to the thymic neuroendocrine tumors are rarely seen. Here, a case of ectopic CS originating from an atypical neuroendocrine tumor has been presented. A 49-year-old woman was hospitalized with symptoms of fatigue, chest pressure, dyspnea, muscle weakness, and resistant hypertension. There was marked hyperpigmentation in the whole-body surface suggestive of adrenocorticotropic hormone (ACTH) excess and there were physical features of CS. There was deep hypokalemia. Basal hormone profile, dexamethasone suppression tests, midnight cortisol, and 24-hour urine cortisol levels were suggestive of ectopic CS. The pituitary magnetic resonance imaging revealed a 5 mm cystic lesion and the patient refused inferior petrosal sinus sampling. Thorax computerized tomography showed an anterior mediastinal mass. A fluorodeoxyglucose-positron emission tomography showed the same mediastinal lesion (suvmax: 11.4), and no other tumor focus was detected. There was an aggressive cortisol excess causing acute respiratory distress syndrome, making it difficult to perform the surgery. We immediately started fluconazole and octreotide therapy and were successful in lowering the cortisol level. Then a complete resection of the tumor had been able to be surgically performed and tumor cells showed strong cytoplasmic immunopositivity with ACTH. A definitive diagnosis of "ACTH secreting atypical thymic carcinoid tumor" was rendered based on the histopathological and immunohistochemical features. There was only surrounding vessel invasion, and no lymphoid or other organ metastases were detected. As there were surrounding vessel invasions, a two-cycle regimen cisplatin-etoposide chemotherapy and radiotherapy were employed. After surgical and medical therapy, the cortisol and ACTH levels turned to normal. The patient is in biochemical and clinical remission and has no tumor recurrence yet. Ectopic ACTH-producing thymic carcinoids are rare but life-threatening tumors because of the underlying malignancy and severe hypercortisolemia. It is important to consider this disease and perform appropriate treatment at the right time. Today, surgery is the standard therapeutic modality if it is possible to perform, but there is not a clear and constant recommendation for nonsurgical therapeutic modalities. Further studies are needed for the optimal treatment strategies.

Abstract Mo016: Atrial Fibrillation Outcomes in Carcinoid Tumor: A National Inpatient Sample (NIS) Study (2018-2020)

Background: Carcinoid Tumor (CT) is a rare type of neuroendocrine tumor with a slow-growing nature. CT can affect different parts of the body, but it most commonly affects the gastrointestinal tract or the lungs. The average age of onset is in the early 60s, affecting around 1.5-1.9 people per 100,000 population. Atrial fibrillation (AF) has been associated with CT, however there is limited data about the outcomes associated with AF in the CT population. We aim to assess the impact of AF on mortality and complications in this population. Methods: The National Inpatient Sample database from 2018 to 2020 was analyzed to identify adult hospitalizations (age > 18) with a diagnosis of CT using appropriate ICD 10 codes. This population was stratified based on concomitant AF. Demographics and complication rates including venous thromboembolic diseases (VTE), acute heart failure (AHF) and acute ischemic stroke (AIS) were studied in these cohorts using a chi-square test for categorical and a t-test for continuous variables. Multivariate regression analysis was further performed to study the impact of AF on complications and mortality after adjusting for relevant confounders. Results: A total of 70504 adult hospitalizations with CT were identified of which 12.71% (N=8964) had AF. 54% of CT admissions were females and the mean age was 64 years. Hospitalizations with CT and AF had a higher rate of VTE, AHF and AIS (Table 1). Multivariate regression analysis revealed higher odds of AHF and AIS with AF in the subpopulation of adults with CT, while the odds of VTE were statistically insignificant. The odds of mortality with AF were also significantly higher in this subpopulation (Table 2). Conclusion: Our study concludes that atrial fibrillation portends a worse prognosis in hospitalizations with Carcinoid Tumor. It also shows a higher rate of AHF and AIS in this subgroup with statistically significant odds. Further studies should be done to study the impact of atrial fibrillation in Carcinoid Tumor patients and treatment guidelines for better management of atrial fibrillation in this vulnerable cohort should be formulated to improve patient outcomes.

Anesthetic key points in a patient with a terminal ileum neuroendocrine tumor and a rare carcinoid left heart disease presented for non-cardiac surgery: case report

BackgroundCarcinoid tumors are rare neuroendocrine malignancies presenting in an increasing number in our center. The incidence of carcinoid tumors is approximatively between 2.5 and 5 cases per 100,000 people of whom about 50% develop carcinoid syndrome. Once the carcinoid syndrome has developed, a carcinoid cardiomyopathy can occur. Carcinoid heart disease (CaHD) remains a serious and rare complication associated with a significant increase in morbidity and mortality. Although carcinoid tumors have been known and studied for several years, there are still scarce data on the anesthetic management and the peri operative period.Case presentationWe describe a case of a Caucasian 44-year-old woman with an unusual presentation of left CaHD with an ileal neuroendocrine tumor and liver metastases. Our preoperative somatostatin administration protocol, limit the cardiac damage. The maintenance of stable hemodynamics, the use of balanced anesthetic technique, all along with a good understanding of the pathology, played a major role in the successful management of anesthesia. This case report allows us to introduce our decision algorithm for the management of this type of pathology in our tertiary hospital, Cliniques Universitaires Saint-Luc.ConclusionDespite the paucity of data, anesthetic management of patients with carcinoid tumor can be safely performed with effective hemodynamic monitoring and a good understanding of the pathophysiology. Knowledge and application of a clear institutional algorithm for octreotide administration and multidisciplinary consultation at a referral center are essential for the management of these patients.

Segmentectomy and wedge resection are equivalent for the treatment of early-stage pulmonary carcinoid tumors: A retrospective cohort study

Currently, there is no consensus regarding the extent of surgery for stage I pulmonary carcinoid (PC) tumors, which encompass typical carcinoid (TC) and atypical carcinoid (AC) tumors. Sublobar resection includes segmental resection and wedge resection; the former is regarded as a type of anatomical resection that is better suited for tumor treatment. Therefore, it needs to be further verified whether differences exist in the effects of the two surgical methods on the survival time of patients. Propensity score matching (PSM) was used. The primary endpoints were cancer-specific survival (CSS) and overall survival (OS) time. Survival differences were analyzed via the Kaplan–Meier method and the log-rank test. There was no significant difference in survival between the sublobar resection and lobectomy groups after PSM in either the TC or AC tumor groups (all p > 0.05). A total of 1680 patients underwent pulmonary wedge resection (TC: n = 1547, AC: n = 133), and 398 patients underwent segmental resection (TC: n = 365, AC: n = 33). After PSM, there were no statistically significant differences in survival, regardless of whether OS or CSS was considered the primary endpoint (OS: p = 0.337; CSS: p = 0.470). Furthermore, segmental resection did not prolong patient survival time compared with wedge resection in different subgroup analyses on the basis of histology, age, and tumor size (all p > 0.05). Finally, the same results were obtained via multivariate Cox analysis (OS: p = 0.153; HR = 1.21; CSS: p = 0.351, HR = 1.32). Sublobar resection could be considered for patients with early-stage typical or atypical pulmonary carcinoid, provided that a rigorous lymph node evaluation is conducted. If the tumor is distant from the pulmonary hilum, either segmentectomy or wedge resection may be performed depending on the specific location of the tumor and the clinical condition of the patient.

The investigation of B12 deficiency leading to the serendipitous diagnosis of gastric carcinoid tumour

Gastric carcinoid is a rare type of gastric malignancy accounting for around 7% of all gastrointestinal neuroendocrine tumours (NETs). While most gastric NETs (gNETs) are readily visible through direct visualisation by upper endoscopy, around 25% of gastric carcinoids are invisible because they are located in the submucosal gastric regions of the body and fundus. gNETs located in the intra-mucosal areas can be identified by gastric mapping; this can be done by taking random gastric biopsies from the antrum, body and fundus. We report a case of a well-differentiated gastric NET type 1 with atrophic gastritis diagnosed on upper endoscopy and pathological immunohistochemistry staining.

Regulation of the Metal Center in Lanthanide Nanoparticles to Achieve Multifunctional Sensing.

Development of a multifunctional sensor is highly desirable. In this work, traces of a carcinoid cancer biomarker of 5-hydroxyindole-3-acetic acid (5-HIAA) in real human urine can be detected by lanthanide nanoparticle Eu-CFC (CFC = 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid) and the sensing devices of the test paper and agarose gel, achieving an ultralow LOD of 0.8 × 10-3 ppm within a sensing time of 2.0 min. Interestingly, by metal center regulation of Tb and Eu codoping, nanoparticle TbEu2-CFC shows high-sensitivity and low-LOD (0.019% v/v) sensing of water in ethanol. The sensing mechanisms are revealed by both experiments and quantum chemical studies.

Pneumonectomy for broncho-pulmonary carcinoids: a single centre analysis of surgical approaches and patient outcomes.

Pneumonectomy is a radical surgical procedure associated with significant morbidity and mortality. Its application in the context of pulmonary neuroendocrine tumours, including carcinoid tumours, requires meticulous preoperative planning and intraoperative precision. This study aims to assess the safety and efficacy of pneumonectomy in the management of these rare and challenging neoplasms. A retrospective analysis of patients who underwent pneumonectomy for pulmonary carcinoid tumours at our institution over a specified period was conducted. Data regarding patient demographics, tumour characteristics, surgical techniques, intraoperative complications, perioperative management, and long-term outcomes were collected and analysed. Between March 2001 and October 2022, 21 patients (7 male, 14 female) with carcinoid tumours underwent pneumonectomy on a total of 459 surgical operations for carcinoid. Preoperative bronchoscopic procedures were conducted in 90.4% of cases, leading to histological diagnoses for most. The median hospital stay was eight days, with no reported perioperative deaths. Median follow-up after surgery was 73 months, with a five-year overall survival of 65.4 months. Recurrences occurred in 28.6% of cases, primarily in atypical carcinoids. Despite the rarity of bronchial carcinoids, pneumonectomy is effective for low-grade malignancies, demonstrating positive short-and long-term outcomes. Radical lymph node dissection is fundamental in pathological staging and overall survival.

Luminescent carbon dots endowed with selective recognition of the carcinoid tumor biomarkers in biological fluids

Biomarkers are commonly used in both basic research and clinical practice as diagnostic tools. Particularly, cancer biomarkers can be applied to the early detection and diagnosis or screening the tumors. Of special note, malignant tumors can release serotonin (5-hydroxytryptamine, 5-HT). In fact, 5-HT is an excellent biomarker for carcinoid tumors since its level in blood plasma is hardly affected by other parameters. Moreover, secretion of 5-HT gives rise to elevated levels of 5-hydroxyindole-3-acetic acid (HIAA), the major metabolite of 5-HT, in urine samples of the patients with carcinoid tumors. 5-HT and HIAA are regarded as eligible biomarkers, of which concentrations in blood plasma and urine samples can be utilized for prognosis, and early diagnosis of carcinoid syndrome. Here, we unveil the facile synthesis and characterization of new Tb(III)-doped carbon dots (CDs) in the present work. Strikingly, CDs exhibited superior features for sensing 5-HT and HIAA. It is of worth to note that the Tb(III)-doped CDs induce phosphorescent response to both 5-HT and HIAA in water. Limit of detections (LODs) for 5-HT and HIAA were found to be 0.44 nM and 0.49 nM, respectively. Remarkably, these are the lowest reported values for luminescent systems to date. Moreover, CDs were utilized as chemosensors for 5-HT and HIAA in simulated blood plasma and synthetic urine samples, respectively. To this purpose, extensive luminescence measurements were performed. Accordingly, the obtained results attested that CDs were promising chemosensors for the detection of both 5-HT and HIAA in simulated blood plasma and synthetic urine samples, respectively. Last but not least, we successfully demonstrate that Tb(III)-doped CDs can be used for the detection of 5-HT in artificial cerebrospinal fluid as well as in conditions mimicking the environment within secretory vesicles where 5-HT is stored. To the best of our knowledge, this is the first example of CDs which can induce remarkable phosphorescent response to 5-HT and HIAA in biological fluids.