Search Results (14)

Background/Objectives: Appendiceal collision tumors (ACTs), defined by the coexistence of two or more histologically distinct neoplastic components within the appendix, are rare entities. We aimed to characterize their clinicopathologic features, management strategies, and outcomes by integrating an institutional case series with a systematic review of the literature. Methods: We retrospectively identified ACTs diagnosed at our institution and performed a PRISMA 2020-guided search of PubMed, Scopus, and Web of Science databases through May 2025 for case reports and case series. Two reviewers screened studies and extracted data on presentation, histologic composition, treatment, approaches and outcomes. Results: ACTs accounted for 4% of appendiceal tumors in our institution, all combining a neuroendocrine neoplasm (NEN) with a low-grade appendiceal mucinous neoplasm. The literature search identified 69 ACTs from 33 studies; pooled with our cases, 74 patients were evaluated. The most common pairings were NEN–appendiceal mucinous neoplasm (53%) and NEN–adenocarcinoma (26%), while three-component tumors were rare (n = 2). Early-stage tumors (pTis–pT1) were uniformly managed with appendectomy or limited resection, in line with established stage-based management algorithms for appendiceal neoplasms. Advanced-stage tumors (pT3–pT4) were treated according to the biologically dominant component, frequently with colectomy and, in high-risk mucinous disease, cytoreductive approaches. Across stages, outcomes appeared to be driven by the non-neuroendocrine component; a coexisting low-grade NEN did not independently confer worse prognosis. In ACTs with an adenocarcinoma component, goblet cell morphology was common, and outcomes appeared similar to those reported for non-collision appendiceal adenocarcinoma. Conclusions: ACTs represent a heterogeneous group in which prognosis is dictated by the non-neuroendocrine component and tumor stage. Low-grade NEN components appear biologically indolent, whereas adenocarcinoma and high-risk mucinous components have been observed to exhibit behavior similar to their solitary counterparts. Full article

Background: Appendiceal neoplasms are rare, but recent data indicate a rising trend, particularly in patients under the age of 50. These tumours are often diagnosed incidentally during histopathological examination. This study has aimed to examine the incidence and histological subtypes of appendiceal neoplasms in a Southern Hungarian population. Methods: Our study included neoplastic appendix specimens processed at the University of Szeged between 2014 and 2023. Results: Neoplasms were identified in 71 cases from 3640 appendectomies (1.9%). Benign lesions were present in 37% of cases (n = 26), with the most common subtype being the sessile serrated lesion (n = 20). Mucinous and malignant neoplasms were found in 63% of cases (n = 45), most frequently low-grade appendiceal mucinous neoplasm (n = 19), followed by neuroendocrine tumour (n = 17). Notably, colorectal neoplasm was identified in 50% of benign, and 42.2% of mucinous and malignant cases during a mean follow-up of 33.4 months. Significant associations were found between histological subtype and age (p = 0.022), complete resection (p = 0.012), presence of vascular invasion (p = 0.007), and localisation of potentially associated colorectal carcinoma (p = 0.018). Additionally, tumour dignity showed significant correlations with tumour, node, metastasis (TNM) stage (p < 0.001), vascular invasion (p = 0.017), and lastly, occurrence (p = 0.031) and localisation (p = 0.003) of associated colorectal carcinoma. Conclusions: The prevalence and characteristics observed in this Southern Hungarian population were consistent with international data, although raw case numbers suggested an upward trend. The high rate of associated colorectal neoplasms underscores the importance of thorough pathological evaluation and long-term surveillance. Full article

Introduction: Appendiceal neuroendocrine neoplasms (aNENs) are the most common malignant appendiceal neoplasms. Localized aNENs are typically managed with an appendectomy; however, right colectomy may be necessary in patients with a high risk of nodal disease. However, the role of right hemicolectomy and the optimal surveillance strategy, particularly for tumors between 1 and 2 cm, remains controversial. Material and Methods: This retrospective, observational study evaluated patients diagnosed with aNENs between January 1995 and July 2015 at two tertiary centers in Ireland and Italy. Data were extracted from a prospectively maintained registry and included clinical, pathological, and therapeutic variables, as well as follow-up outcomes. Results: Forty-three patients (41.8% male; median age 27.5 years) were included, with a median follow-up of 49 months. The median tumor size was 6.4 mm (range: 0.6–40 mm). The majority were G1 tumors (58%), and staging distribution was predominantly Stage I (60%). While no significant differences in demographics or tumor features were observed between centers, completion right hemicolectomies were more frequent in the Irish cohort (p = 0.04). Follow-up practices varied, with more intensive imaging and biochemical monitoring observed in the Italian cohort. Overall prognosis was excellent, with a single case of recurrence during the study period. Conclusions: Most aNENs are effectively managed with appendectomy alone, and routine follow-up may be unnecessary in the absence of adverse pathological features. Accurate risk stratification, driven by comprehensive histopathological assessment, is critical for optimizing management and surveillance strategies. Full article

Background/Objectives: Appendiceal cancer (AC) is a rare and understudied malignancy with limited genomic data available to guide clinical interventions. Historically treated as a subtype of colorectal cancer, AC is now recognized as a distinct disease with unique histologic subtypes and molecular features. This review aims to consolidate current genomic data across AC subtypes and explore the clinical relevance of recurrent mutations. Methods: A systematic literature review was performed in accordance with general Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) guidelines. Using search engines such as PubMed and Web of Science, we selected studies based on relevance to AC genomics using search terms such as “appendix cancer”, “appendiceal cancer”, “pseudomyxoma peritonei”, “sequencing”, “mutation”, and “genotype”. Results: AC comprises five major histologic subtypes—appendiceal neuroendocrine neoplasms (ANENs), mucinous appendiceal neoplasms (MANs), goblet cell adenocarcinomas (GCAs), colonic-type adenocarcinomas (CTAs) and signet ring cell adenocarcinomas (SRCs)—each with unique clinical behaviors and mutational profiles. Low-grade tumors, such as ANENs and MANs, frequently harbor KRAS and GNAS mutations, while high-grade subtypes, such as CTAs and SRCs, are enriched for TP53, APC, and SMAD gene alterations. GCA tumors exhibit a distinct mutational spectrum involving chromatin remodeling genes such as ARID1A and KMT2D. Compared to colorectal cancer, AC demonstrates lower frequencies of APC and TP53 mutations and a higher prevalence of GNAS mutations, consistent with a pathological divergence from CRC. Conclusions: The genomic heterogeneity of AC is commensurate with its histological complexity and has important implications for diagnosis, prognosis and treatment. While certain actionable mutations are present in a subset of tumors, large-scale genomic characterization efforts and development of subtype-specific models will be essential for advancing precision medicine in AC. Full article

Goblet cell adenocarcinomas (GCAs) are an exceedingly rare subtype of tumors, almost exclusively occurring in the appendix, and characterized by features overlapping both adenocarcinomas and neuroendocrine tumors (NETs), which has historically led to confusion and varied nomenclature. This study presents a comprehensive review of the literature highlighting particularities of this type of malignancy, starting from a rare case of a 54-year-old female operated on in our clinic for an appendiceal tumor, initially suspected to be a mucinous neoplasm based on colonoscopic biopsy, which was ultimately confirmed to be goblet cell adenocarcinoma on both intraoperative frozen section and definitive pathological examination. Exhibiting signs and symptoms associated with an abdominal mass, she underwent a right hemicolectomy with partial omentectomy for locally advanced, high-grade, invasive goblet cell adenocarcinoma of the appendix with lymphatic macro metastases and epiploic invasion, categorized as AJCC stage IVb carcinomatosis. The patient received FOLFOX adjuvant. Six months later, she required reoperation due to the progression of carcinomatosis, which was again confirmed histopathologically. A second-line oncological protocol comprising irinotecan, capecitabine, and bevacizumab was initiated. Given the rarity of GCAs and the absence of a consensus on nomenclature, classification, and diagnostic criteria, we conducted a comprehensive literature review to highlight current trends related to this entity, including its classification within different systems (Tang, Yozu, WHO, AJCC), as well as the therapeutic surgical approaches—ranging from simple appendectomy to extensive multiorgan resection, cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC), and the use of systemic therapy. Adhering to these recommendations will enhance communication among pathologists, surgeons, and oncologists regarding the natural history and prognosis of this rare malignancy. Full article

Background: Appendiceal diverticulitis is a rare and poorly understood condition of the appendix. The diagnosis of appendiceal diverticulitis is challenging due to its rarity and a clinical presentation that often mimics other ileocecal disorders. Unlike acute appendicitis, appendiceal diverticulitis may be associated with a higher risk of perforation, increased mortality, and a potential link to neoplasms. However, further research is necessary to enhance our understanding of its epidemiology, risk factors, clinical presentation, and outcomes. Case Report: A 53-year-old male presented to the emergency department with right lower abdominal pain. On physical examination, tenderness was noted in the right lower quadrant, without rebound tenderness or muscle guarding. Laboratory tests revealed leukocytosis and elevated C-reactive protein (CRP) levels. Ultrasonographic imaging of the ileocecal region suggested acute appendicitis, leading to a decision for surgical intervention. Laparoscopic exploration revealed multiple cylindrical, red, and edematous herniations, up to 4 mm in size, on the surface of the vermiform appendix. An appendectomy was performed. Histopathological examination confirmed appendiceal diverticulitis with surrounding peridiverticulitis. The surgery and early postoperative course were uneventful. Literature review: The study included 5 retrospective studies and 30 case reports, analyzing a total of 112 patients with appendiceal diverticulitis. Of these, 65.5% were male and 34.5% were female, with a median age of 49 years (IQR: 39–59). The most commonly reported clinical findings included pain in the right iliac fossa or right lower abdominal quadrant (56.5%), nausea (18.9%), vomiting (9.8%), rebound tenderness (24.6%), fever (15.6%), leukocytosis (25.4%), and elevated C-reactive protein levels (16.4%). Diagnosis was confirmed histopathologically in 86.9% of the cases via computed tomography imaging in 4.1% and ultrasonography in 1.6%. A histopathological analysis identified five neoplasms (4.1%), including two sessile serrated adenomas, two neuroendocrine carcinoids, and one mucinous tumor. Appendectomy was the treatment of choice, with no intraoperative or postoperative complications recorded and no mortality reported. The median hospital stay was 6.8 days (IQR: 3.0–6.8). Conclusions: Appendiceal diverticulitis should be considered as a differential diagnosis in patients presenting with symptoms resembling acute appendicitis. Early diagnosis and treatment are essential to reduce morbidity and mortality. Appendectomy is a safe and effective treatment approach for appendiceal diverticulitis. Full article

Background/Objectives: Appendiceal neuroendocrine neoplasms (ANENs) are usually found incidentally during histology examination after appendectomy for appendicitis. Due to their rarity in pediatric populations, there is no consensus on treatment or follow-up. The analysis of patients with ANENs of our and other studies will increase the understanding of this tumor. Methods: Pediatric patients with ANENs were uniformly managed at our center between 1998 and 2023. Patients’ presenting symptoms, surgery, tumor histology, post-surgical work-up, follow-up and outcome were analyzed. Results: Our report describes 17 patients with a diagnosis of ANEN after appendectomy. The median age was 14 years (range of 4–17 years). Tumors were located at the tip of the appendix in 58.8% of cases and only one had a diameter >1 cm. All were well-differentiated tumors with free resection margins. The submucosa was invaded in five cases, muscularis propria in eight and subserosa in four. Post-appendectomy work-up included tumor marker measurement, abdominal ultrasound and computed tomography or magnetic resonance imaging, chest X-ray and octreotide scintigraphy. No residual tumors or metastases were detected. Additional surgery was not necessary. Follow-up was carried out for a median duration of 6 years (range of 1–10 years). Only one patient was lost to follow-up and all other patients are alive without tumor recurrence. Conclusions: The tumor characteristics of our patients confirmed data from the literature. With the lack of a sufficient number of large prospective trials, it is important to add more information to confirm the benign nature and excellent outcome of this tumor, even without additional surgery. Consensus guidelines are needed for ANENs in pediatric populations. Full article

Background: Appendiceal neuroendocrine tumors (NETs) rank as the third most frequent neoplasm affecting the appendix, originating from enterochromaffin cells. This study aims to evaluate the influence of various prognostic factors on the mortality rates of patients diagnosed with NETs of the appendix. Methods: Conducted retrospectively, the study involved 3346 patients, utilizing data sourced from the Surveillance, Epidemiology, and End Results (SEER) database. Our analysis centered on investigating demographic characteristics, clinical features, overall mortality (OM), and cancer-specific mortality (CSM) among the cohort. Variables showing a p-value < 0.1 in the univariate Cox regression were incorporated into the multivariate Cox regression analysis. A Hazard Ratio (HR) > 1 indicated an unfavorable prognosis. Results: In the multivariate analysis, higher OM and CSM were observed in males, older age groups, tumors with distant metastasis, poorly differentiated tumors, and those who underwent chemotherapy. Non-Hispanic Black individuals showed elevated mortality rates. Conclusion: Delayed diagnosis may contribute to the increased mortality in this community. Improved access to healthcare and treatment is crucial for addressing these disparities. Larger prospective studies are needed to pinpoint the underlying causes of elevated mortality in non-Hispanic Black populations, and randomized controlled trials (RCTs) are warranted to evaluate therapies for advanced-stage appendix NETs. Full article

The 5th edition of the World Health Organization (WHO) classification of tumors of the digestive system distinguishes four categories of appendiceal tumors (ATs): serrated lesions and polyps, mucinous neoplasms, adenocarcinomas, and neuroendocrine neoplasms (NENs). The differential diagnosis of ATs can be challenging in medical practice, due to their rarity and lack of data from randomized controlled trials on a large, diverse group of patients. ATs are usually noted in specimens obtained during appendectomies due to clinical acute appendicitis. In the European population, most ATs (65%) occur over the age of 50 and among women (56.8%). According to histological type, 54.6% are neuroendocrine tumors (NETs); 26.8% cystic, mucinous, and serous neoplasms; and 18.6% adenocarcinoma not otherwise specified (NOS). On pathologic analysis, most AT findings are benign lesions or small NENs that do not require further therapeutic measures. The presence of appendiceal mucinous neoplasm (AMN) can lead to pseudomyxoma peritonei (PMP). While the multimodal treatment for abdominal malignancies has evolved over the past several decades, the clinical workup and treatment of ATs remain a challenge. Therefore, this review aims to describe the diagnostic possibilities, molecular-based diagnosis, staging, differences in the treatment process, and prognostic factors associated with ATs. Full article

Background: Neuroendocrine tumors (NETs) are rare tumors that arise from neuroendocrine cells and are the most common tumors of the appendix. NETs of the appendix usually cause no symptoms and often go unnoticed until they cause acute appendicitis or are discovered during an accidental appendectomy. As the trend towards the conservative treatment of acute appendicitis increases in the pediatric population, the question arises as to whether the majority of NETs go undetected and are only discovered at an advanced stage. The purpose of the proposed study is to review the incidence and outcomes of treatment for NETs of the appendix in children and include the data presented in the data pool for further review. Methods: From 1 January 2009 to 1 November 2023, a total of 6285 appendectomies were performed in two large pediatric centers in Croatia. After a retrospective review of the case records and histopathologic findings, a total of 31 children (0.49%) were diagnosed with NET of the appendix and included in the further analysis. The primary outcome of this study was the incidence and treatment outcome of pediatric patients diagnosed with NET of the appendix. Secondary outcomes included the patients’ demographic, clinical, and laboratory data and the histopathologic characteristics of tumor species. Results: The overall incidence of NETs of the appendix was stable over the study years, with minor fluctuations. The median age of patients was 14 (interquartile range—IQR: 12, 16) years, with a female predominance (64.5%). The majority of patients (96.8%) presented with acute abdominal pain and underwent appendectomy because acute appendicitis was suspected. Acute appendicitis was confirmed by histopathology in 18 (58%) cases. NETs of the appendix were not detected preoperatively in any of the patients. Among patients with confirmed acute appendicitis, most (n = 14; 77.8%) were found to have non-perforated acute appendicitis. In most children, the tumor was located at the tip of the appendix (n = 18; 58.1%), and the majority of tumors had a diameter of less than 1 cm (n = 21, 67.7%). The mitotic count (n = 25, 80.6%) and Ki-67 proliferation index (n = 23, 74.2%) were low in most patients, so most tumors were classified as NET G1 (n = 25, 80.6%), while NET G2 and NET G3 were found in four (12.9%) and two (6.5%) patients, respectively. All children were treated with appendectomy only. The median follow-up time was 54 (IQR: 24, 95) months. Conclusions: The incidence of appendiceal NET among pediatric patients is very low. NET occurs most frequently in adolescents, with a female predominance. Most tumors are less than 1 cm in diameter, located at the tip, and associated with non-perforated appendicitis. Appendectomy is the treatment of choice, and major surgery was not necessary in our cohort. Full article

Appendix neuroendocrine neoplasm (ANEN) treatment is based on tumor size and proliferation markers. Recently, the role of the follicle-stimulating hormone receptor (FSHR) from the clinical perspective has also been increasingly discussed. The FSHR is expressed in the endothelial cells of both intratumoral and peritumoral blood vessels, where it contributes to neoangiogenesis and blood vessel remodeling. FSHR expression is associated with a range of tumor types, such as gastrointestinal tumors, and it is not detected in healthy tissues located more than 10 mm from the tumor site or in tumor lymphatics. In this study, we evaluated the expression of FSHR and CD31 in the blood vessels of ANENs in females and males with confirmed histopathology. We conducted a quantitative analysis of the immunohistochemical reactions and found a higher number of microvessels in the mucosa and submucosa of neuroendocrine tumors in the appendix. A higher level of FSHR expression was observed in women. Future research should consider whether an elevated number of blood vessels along with a strong pattern of FSHR expression may influence future treatment strategies. Full article

Appendiceal neuroendocrine neoplasms (ANENs) usually present as incidental findings at the time of appendectomy for acute appendicitis. They are rare, accounting for only 0.5–1% of intestinal neoplasms; they are found in 0.3–0.9% of all appendectomy specimens. They are usually sporadic tumors. There are several histological types including well-differentiated neuroendocrine tumors (NETs), poorly differentiated neuroendocrine carcinomas (NECs), and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs). Histologic differentiation and the grade of well-differentiated NETs correlate with clinical behavior and prognosis. Management varies based on differentiation, aggressiveness, and metastatic potential. There is debate about the optimal surgical management for localized appendiceal NETs that are impacted by many factors including the tumor size, the extent of mesoappendiceal spread, lymphovascular invasion and perineural involvement. In addition, the data to guide therapy in metastatic disease are limited due to the paucity of these tumors. Here, we review the current advances in the management of ANENs within the context of a multidisciplinary approach to these tumors. Full article

Goblet cell carcinoma (GCC) is a rare primary tumor of the appendix characterized by both epithelial and neuroendocrine components containing goblet cells. While in the past, the GCC has been associated with neuroendocrine tumors, recent studies consider that GCC is closer to adenocarcinoma than a neuroendocrine component. The association between gastro-intestinal (GI) carcinoids and second primary malignancies (SPMs) is widely described in the literature, but there is no reported case of GCC and synchronous adjacent adenocarcinoma of the colon. We describe the first case in the literature, to our knowledge, of synchronous colorectal adenocarcinoma of the cecum and GCC of the appendix that are incidentally discovered in the resected primary cancer specimen. The association between the two neoplasms seems to be not causal and maybe the “paracrine-effect theory” may explain the development of a second tumor close to the primary. Full article

Neuroendocrine neoplasms (NENs) are the most common tumor of the appendix and have an excellent prognosis. Appendiceal tumors diagnosed between 1989 and 2019 were reviewed, and clinical data were collected from patient files. Part of the series was immuno-profiled for markers related to cell cycle proliferation and/or senescence-type, apoptotic, and metastatic potential. Appendix NENs were detected in 74 patients, with 0.47% of incidence per appendectomy. The median age of the patients was 21.5 years, with two age peaks of incidence at 17.0 and 55.2 years. The median tumors size was 5.8 mm, and most were smaller than 10 mm. Lymphovascular and perineural invasion, as well as necrosis, was associated with larger tumor size. G1 tumors composed 96.0% of the cohort. The presence of moderate/strong p16 and the absent/low Bcl-2 expression was frequently observed and associated with a smaller size. This study represents one of the largest cohorts and with a long follow-up. For tumors smaller than 10 mm appendicectomy was sufficient as a curative procedure, as revealed by the good outcome. This series presented a 100% disease-free survival. The indolent phenotype of appendix NENs is supported by the expression of markers that point towards a strong inhibition of cell replication and growth inhibition. Full article