Selective Gastrectomy with Knowledge of Gastric Anatomy and Blood Supply are Key to Complete Tumour Removal in Advanced Pseudomyxoma: Single-Centre Experience with 120 Gastrectomies Over 20 Years.

BACKGROUND: The role of gastrectomy to achieve complete cytoreduction (CCR) for pseudomyxoma peritonei (PMP) is controversial due to uncertain risk/benefit ratio. The outcomes of patients who gastrectomy over a twenty-year period in a high-volume unit are reported. METHODS: All patients requiring gastrectomy to achieve CCR for appendiceal PMP between 2000 and 2020 were reviewed. Demographics, disease, operative, complication, and survival data were analysed. The first and second decades were compared. RESULTS: A total of 2148 patients underwent CRS and HIPEC, of which 78% had CCR. Gastrectomy was performed in 7.1%. Median age was 55 years, and 52% were female. Among gastrectomy patients, 94.2% had ≥1 elevated tumour marker, and 18% had high-grade disease. Median PCI was 30, and 30% required subtotal colectomy. Clavien-Dindo III-IV complications occurred in 32%, and 90-day mortality was 1.75%. Median survival was 104 months, and 10-year OS was 47%. Comparing the two decades, total CRS cases almost tripled, with a greater proportion achieving CCR (82.2% vs. 67.8%) but fewer requiring gastrectomy (5.3% vs. 13.5%). In those who had gastrectomy, disease was more advanced (higher PCI, more high-grade disease, more colectomies) in the later period. However, on multivariable analysis, there was no difference in survival between decades. High-grade histology was the only predictor of survival. CONCLUSIONS: Gastrectomy can achieve good long-term survival with low mortality and acceptable morbidity and should not deter surgeons from achieving CCR. However, increasing experience shows CCR can be achieved, preserving the stomach in the majority of cases through careful consideration of the anatomy and gastric blood supply.

Is appendoscope a new option for the treatment of acute appendicitis?

Acute appendicitis is a common surgical emergency. It is commonly caused by obstruction of the appendiceal lumen due to fecaliths, tumors, or lymphoid hyperplasia. For over a century, appendectomy has been the primary treatment for acute appendicitis. Abraham Groves performed the first open appendectomy in 1883. In 1983, Kurt Semm completed the first laparoscopic appendectomy, heralding a new era in appendectomy. However, appendectomy is associated with certain complications and a rate of negative appendectomies. Studies have suggested controversy over the impact of appendectomy on the development of inflammatory bowel disease and Parkinson's disease, but an increasing number of studies indicate a possible positive correlation between appendectomy and colorectal cancer, gallstones, and cardiovascular disease. With the recognition that the appendix is not a vestigial organ and the advancement of endoscopic te-chnology, Liu proposed the endoscopic retrograde appendicitis therapy. It is an effective minimally invasive alternative for treating uncomplicated acute appendicitis. Our team has developed an appendoscope with a disposable digital imaging system operated through the biopsy channel of a colonoscope and successfully applied it in the treatment of appendicitis. This article provides an overview of the progress in endoscopic treatment for acute appendicitis and offers a new perspective on the future direction of appendiceal disease treatment.

Endometriosis of the appendix: prevalence, associated lesions, and proposal of pathogenetic hypotheses. A retrospective cohort study with prospectively collected data.

OBJECTIVE: To assess the prevalence of endometriosis of the appendix and the association with other pelvic localizations of the disease and to provide pathogenesis hypotheses. METHODS: Monocentric, observational, retrospective, cohort study. Patients undergoing laparoscopic endometriosis surgery in our tertiary referral center were consecutively enrolled. The prevalence of the different localizations of pelvic endometriosis including appendix involvement detected during surgery was collected. Included patients were divided into two groups based on the presence of appendiceal endometriosis. Women with a history of appendectomy were excluded. MEASUREMENTS AND MAIN RESULTS: Four hundred-sixty patients were included for data analysis. The prevalence of appendiceal endometriosis was 2.8%. In patients affected by endometriosis of the appendix, concomitant ovarian and/or bladder endometriosis were more frequently encountered, with prevalence of 53.9% (vs 21.0% in non-appendiceal endometriosis group, p = 0.005) and 38.4% (vs 11.4%, p = 0.003), respectively. Isolated ovarian endometriosis was significantly associated to appendiceal disease compared to isolated uterosacral ligament (USL) endometriosis or USL and ovarian endometriosis combined (46.2% vs 15.4% vs 7.7%, p < 0.001). Poisson regression analysis revealed a 4.1-fold and 4.4-fold higher risk of ovarian and bladder endometriosis, respectively, and a 0.1-fold risk of concomitant USL endometriosis in patients with appendiceal involvement. CONCLUSION: Involvement of the appendix is not uncommon among patients undergoing endometriosis surgery. Significant association was detected between appendiceal, ovarian, and bladder endometriosis that may be explained by disease dissemination coming from endometrioma fluid shedding. Given the prevalence of appendiceal involvement, counseling regarding the potential need for appendectomy during endometriosis surgery should be considered.

Histopathological Diagnosis of a Case of Mucin-Secreting Adenocarcinoma of the Appendix.

Mucin-secreting adenocarcinoma of the appendix is a very rare, slow-growing, mucin-producing epithelial neoplasm of the appendix. It is usually found accidentally in an appendicectomy specimen with the presentation of acute appendicitis in most patients or when there is a rupture of the primary tumor with the mucin spreading along with the tumor cells in the entire peritoneal cavity. Here we describe a case of low-grade (well-differentiated) mucin-secreting adenocarcinoma in the appendix. A 48-year-old female presented with complaints of abdominal distension with no other complaints of fever, pain, or breathlessness. Carcinoembryonic antigen levels were 44.8 ng/mL. Cytoreduction surgery of bilateral ovaries was done. The final histopathological diagnosis was reported as low-grade (well-differentiated) mucin-secreting adenocarcinoma of the appendix staged at pT4b pNx pM1c. Pseudomyxoma peritonei is a very feared complication and also, at times, the only presenting symptom where there is an accumulation of mucin in the intra-abdominal cavity due to the spread of mucin-secreting cells, which in turn causes an increase in the abdominal girth along with discomfort for the patient. The mainstay of treatment remains cytoreductive surgery along with hyperthermic intraperitoneal chemotherapy.

Appendiceal Adenocarcinoma Presenting as Palpable Breast Masses.

Appendiceal tumors are rare and are most commonly diagnosed incidentally during surgical removal of the appendix for acute appendicitis. Appendiceal adenocarcinomas are the most common appendiceal cancers, and their metastasis to the breast is extremely uncommon. We report a case of mucinous appendiceal adenocarcinoma presenting with breast metastasis. To the best of our knowledge, there has been only one case published in the literature about appendiceal cancer with metastasis to the breast. Interestingly, our patient's initial presentation was palpable breast masses rather than gastrointestinal symptoms.

Appendicular Neuroendocrine Tumours: An Unusual Cause of Hydronephrosis.

Although neuroendocrine tumours (NETs) are predominantly located in the gastrointestinal tract, pancreas, and lungs, they can also occur in uncommon places such as the biliary system, prostate, breast, head, neck, and even the spinal cord. We present the case of a 30-year-old woman who was referred to the urology clinic for right ureterohydronephrosis. Because the contrast-enhanced CT scan did not show signs of kidney stones or an upper urothelial tract cell carcinoma and was combined with renal scintigraphy, the kidney was not functional, and a left nephrectomy was performed. During the surgery, it was observed that the appendix was attached to the ureter by a tiny tumour. In addition, an appendectomy was also conducted. The pathological test indicated the presence of a NET that had invaded the ureter. The diagnosis was confirmed by immunohistochemical staining. The tissue has been positive for chromogranin and synaptophysin staining. Our work highlights the infrequency and difficulty of diagnosing NETs that invade the ureter. Conducting a thorough histological evaluation in patients with uncertain histopathological diagnoses is essential.

Survival among 148 patients with an incidentally detected appendiceal tumours at surgery for acute appendicitis: a population-based cohort follow-up study.

PURPOSE: To investigate the long-term prognosis of appendiceal tumours incidentally detected at appendicectomy for suspicion of benign appendicitis. METHODS: A retrospective register-based single centre cohort study was carried out, using data from the local acute appendicectomy quality register of cases operated on at the Department of Surgery, South General Hospital, Stockholm, Sweden. The local colorectal cancer register was also used to identify appendix tumours. The study period was between January 2004 and January 2023. Survival was calculated according to the Kaplan-Meier method. RESULTS: A total of 11,888 patients were registered in the acute acute appendicectomy register, 54% males and 46% females, median age 32 (Q1 = 21, Q3 = 47) (with 33.7% were 41 years or older). From the appendicectomy and colorectal registers 148 (1.2% of the total cohort) appendiceal tumours were found; 60% in females and 40% in males, median age 56 (Q1 = 43, Q3 = 70) (with 78.4% being 41 years or older). Tumours found were: Low grade Appendiceal Mucinous Neoplasms (LAMN, N = 64); Neuroendocrine Tumours (NET N = 24); adenocarcinomas or other form of carcinomas (N = 57); and adenomas (N = 3). The overall 5-year survival in patients operated for LAMN was 96.8%, for NET 93.3% and for adenocarcinoma 69.7%. The overall 5-year survival for all tumour patients was 85.7%. For the younger patients (< 51 years) with LAMN and NET, almost all survived to the end of follow-up. Survival of patients in the carcinoma group was statistically significantly lower than for the LAMN and NET groups, especially in females 51 years or older. In the group of tumour patients undergoing surgery (n = 146), primary surgery was laparoscopic in 47% and open in 52%. Two patients did not undergo surgery due to widespread disease. In 64% of cases operation was acute, whereas it was delayed and/or planned in 34%. Most procedures were laparoscopic appendicectomy 36%, followed by open appendicectomy 30%, right-sided hemicolectomy 14.6% (open 11.6% and laparoscopic 3%, acute operation 5.5%), ileocaecal resection 5% (acute operation 3.4%), and staging laparoscopy 7%. In 38% of the operated patients the tumour was discovered incidentally at histopathology examination. Two patients had CRS and HIPEC as the initial operation. Forthy-three per cent of the 146 tumour patients operated underwent a second procedure: CRS and HIPEC in 23.3% and right-sided hemicolectomy in 13.6% (laparoscopic 8.2% open 5.4%). CONCLUSION: Survival was high for patients with incidentally detected appendiceal LAMN or NET, but not so for carcinoma. Survival was lower in the carcinoma group older than 50 years, especially those sick and females.

A Case of Low-Grade Appendiceal Mucinous Neoplasm: The Role of Preoperative Imaging and Surgical Technique in Achieving Favorable Outcomes.

Appendiceal mucinous neoplasms may present without symptoms or with chronic pain in the right lower quadrant. This report describes a case of a 35-year-old woman who presented with chronic right lower quadrant pain and was found to have a low-grade appendiceal mucinous neoplasm (LAMN). Physical examination revealed localized tenderness in the right lower quadrant with no additional symptoms. Preoperative laboratory results were normal, and a CT scan revealed a cystic appendiceal lesion with an internal calcification, initially mistaken for a fecalith, which led to the decision for exploratory laparotomy. Intraoperative findings confirmed the presence of a cystic-like appendiceal lesion, and an open appendectomy was performed. Histopathological examination revealed a low-grade appendiceal mucinous neoplasm (LAMN) confined to the mucosa, without evidence of metastatic disease. The patient had an uneventful recovery and required no additional treatment. This case highlights that surgical intervention with proper technique for confined appendiceal neoplasms, combined with effective preoperative imaging and thorough histopathological examination, is crucial for diagnosis and effective management, ensuring favorable outcomes.

Comparison of EPIC Versus HIPEC in the Treatment of Colorectal Peritoneal Metastases and Appendix Tumors Using Inverse Probability of Treatment Weighting.

BACKGROUND: The selection of hyperthermic intraperitoneal chemotherapy (HIPEC) or early postoperative intraperitoneal chemotherapy (EPIC) for peritoneal metastases from colorectal cancer or appendiceal neoplasms following cytoreductive surgery (CRS) depends on the surgeon's discretion. This study was designed to compare postoperative and oncologic outcomes of HIPEC and EPIC using inverse probability of treatment weighting (IPTW). METHODS: This study included 175 patients who received HIPEC or EPIC following CRS at a single tertiary university hospital between December 1999 and December 2020. Inverse probability of treatment weighting analysis was performed to control for pretreatment characteristics between the two groups. Multivariate analysis was performed to determine factors associated with postoperative and survival outcomes. RESULTS: After IPTW, no significant differences in baseline demographics and tumor characteristics were observed between the two groups. The HIPEC group had a significantly longer operation time than the EPIC group. The EPIC group showed a significantly higher postoperative mortality rate than the HIPEC group. Operation time (odds ratio [OR] 1.01; 95% confidence interval [CI] 1.01-1.02; p < 0.001), bowel anastomosis (OR 7.25; 95% CI 1.16-45.2; p = 0.034), neoadjuvant chemotherapy (OR 7.62; 95% CI 1.85-31.4; p = 0.005), and EPIC (OR 8.76; 95% CI 2.16-35.5; p = 0.002) were independent risk factors for major surgical complications. No association was observed between intraperitoneal chemotherapy type and major hematologic toxicity, overall survival, progression-free survival, or peritoneal progression-free survival. CONCLUSIONS: EPIC was a risk factor for major surgical complications. Survival outcomes were similar between the two types of intraperitoneal chemotherapy.

Gastroenteropancreatic neuroendocrine tumors in children and adolescents.

BACKGROUND: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare in children and adolescents. Standard management of these tumors has not been well established due to their rarity in this age group. We aimed to report the clinical and pathological characteristics of patients with this rare disease followed and treated between the years 1993-2022. MATERIALS AND METHODS: The medical records of patients with GEP-NETs were reviewed. RESULTS: Fourteen patients (11 girls, 3 boys) were diagnosed with GEP-NET. The median age was 13 (9-18) years. Tumor localization was the appendix in 12, stomach in one and pancreas in one patient. Mesoappendix invasion was detected in four patients two of whom underwent right hemicolectomy (RHC) and lymph node dissection (LND). Of those, one patient had lymph node involvement. The other two had not further operations. Somatostatin was used in one with pancreatic metastatic disease and the other with gastric disease after surgery. No additional treatment was given in other patients. All patients are under follow-up without evidence of disease at a median follow-up of 85 months (7-226 months). CONCLUSION: GEP-NETs should be considered in the differential diagnosis of acute appendicitis and in cases with persistent abdominal pain. In children, there is invariably a favorable prognosis, and additional surgical interventions other than simple appendectomies generally do not provide benefits. Mesoappendix invasion may not necessitate RHC and LND.

Colorectal endometriosis - a challenging, often overlooked cause of colorectal pathology: a clinicopathological review of 114 cases.

The colon is the most common site for endometriosis outside the genital tract. It has a varied presentation and can mimic numerous other conditions, both clinically and pathologically. We investigated the clinicopathological features of a series of colorectal endometriosis with a particular emphasis on the features seen in cases with colonic mucosal involvement. A total of 114 consecutive cases of colorectal endometriosis were reviewed. Forty-eight percent did not have a prior diagnosis of endometriosis and in 34 patients (30%) the endometriosis was determined as the cause for the presentation. Mucosal involvement was present in 31 specimens. Features of chronic colitis were seen in the adjacent mucosa in 90% of cases whilst there were glandular changes mimicking adenocarcinoma in two cases (1.8%). Fifty percent of cases with mucosal involvement also showed glands with a hybrid intestinal-endometrial phenotype by morphology and/or by immunohistochemistry. Endometriosis is an important mimic of other conditions.

Visualizing the landscape of appendiceal tumor research after 2010: A bibliometric study.

BACKGROUND: Despite the rarity of appendiceal tumors, research in this field has intensified, resulting in a growing number of studies and published papers. Surprisingly, no comprehensive bibliometric analysis has specifically addressed appendiceal tumors. AIM: To offer a thorough analysis of the current landscape and future trends in appendiceal tumor research. METHODS: In our bibliometric analysis studies, we explored the Web of Science Core Collection database. The bibliographic details of the chosen publications were automatically converted and analyzed using the bibliometric package in the R environment. Additionally, we employed VoSviewer to create cooperation network maps for countries, institutions, and authors, as well as clustering maps for keywords. Furthermore, CiteSpace, another software tool, was utilized to build dual-map overlays of journals and analyze references with citation bursts. RESULTS: Our study included 780 English-language articles published after 2010. The number of related publications and citations has increased in the past decade. The United States leads in this area, but there is a need to improve cooperation and communication among countries and institutions. Co-occurrence analysis also revealed close collaboration among different authors. Annals of Surgical Oncology was the most influential journal in this field. Analysis of references with high co-citations and references with citation bursts, consistent with analysis of keywords and hotspots, indicated that current research primarily centers on the classification and management of appendiceal mucinous neoplasms and consequent pseudomyxoma peritonei. Despite the abundance of clinical studies, a greater number of in-depth basic research studies should be conducted. CONCLUSION: Current research on appendiceal tumors focuses on classification and management of appendiceal mucinous neoplasms and pseudomyxoma peritonei. Enhanced collaboration and basic research are vital for further advancement.

Resection of polyps involving the appendiceal orifice by combined endo-laparoscopic surgery: Two case reports.

BACKGROUND: The management of polyps involving the appendiceal orifice (AO) presents notable challenges. Endoscopic resection is frequently hindered by operational complexities, a heightened risk of incomplete removal, and an elevated risk of procedural complications, including appendicitis. Conversely, surgical resection may entail unnecessary excision of intestinal segments, leading to potential morbidity. CASE SUMMARY: Here, we reported two patients who presented with polyps deeply situated within the AO, with indistinct boundaries making it challenging to ensure completeness using traditional endoscopic resection. To overcome these challenges, we employed combined endo-laparoscopic surgery (CELS), achieving curative resection without postoperative complications. CONCLUSION: The application of CELS in managing polyps involving the AO is emerging as a safe and effective treatment modality.

Pelvic Diagnostic Challenges of Appendiceal Neoplasm Mimicking a Hematosalpinx: A Case Report.

Appendiceal mucinous neoplasms are rare and can be easily misdiagnosed as adnexal masses. Fertility is a concern in cases requiring cytoreductive surgery involving the ovaries and if hyperthermic intraperitoneal chemotherapy is considered. We present the case of a 35-year-old patient with primary infertility who was suspected to have a hematosalpinx on ultrasonography and magnetic resonance imaging (MRI) but was found to have an appendiceal mucinous neoplasm on laparoscopy. Fertility preservation was offered to this patient. Appendiceal mucinous neoplasms should be considered in the differential diagnosis of patients in their reproductive years presenting with adnexal masses. Fertility preservation should be discussed with these patients, especially when gonadotoxic treatments are planned.

Appendiceal goblet cell adenocarcinoma newly classified by WHO 5th edition: a case report (a secondary publication).

BACKGROUND: Appendiceal goblet cell adenocarcinoma (AGCA) is a newly proposed cancer type in the 5th edition of the WHO Classification of Tumours in 2019. We experienced this rare form of appendiceal primary neoplasm. CASE PRESENTATION: An 85-year-old male presented a positive fecal occult blood test. A series of imagings revealed a type 1 tumor, located on the appendiceal orifice. The subsequent biopsy made the diagnosis of signet-ring cell carcinoma. Consequently, he underwent the laparoscopic-assisted ileocecal resection. Initially, the tumor was suspected to be a Goblet cell carcinoid (GCC). There was a discrepancy between the histological and immunostaining findings: the tumor cells exhibited morphological similarities to GCCs, however displayed limited staining upon immunostaining. Ultimately, we concluded that the tumor should be classified as AGCA, by following WHO 5th Edition. AGCA represents a newly categorized subtype of adenocarcinomas. Because of our preoperative suspicion of malignancy, we performed tumor resection with regional lymph node dissection, despite the fact that most appendiceal malignant tumors are typically identified after an appendectomy. CONCLUSION: We experienced a case that provides valuable insights into the comprehension of AGCA, a recently established pathological entity in the WHO 5th Edition. This article is an acceptable secondary publication of a case report that appeared in Azuma et al. (J Jpn Surg Assoc 83:1103-1108, 2022).

Clinical Significance of Circulating Tumor Cells in Epithelial Appendiceal Neoplasms with Peritoneal Metastases.

Appendiceal tumors are uncommon and, at times, discovered incidentally during histological examination. The histopathological classification of the disease is complex and has generated some controversy. The analysis of circulating tumor cells can be used for the early detection of metastatic potential. The aim of the present study was to examine the prognostic value of circulating tumor cells in patients with appendiceal tumors and peritoneal metastases. To our knowledge, this is the first study to examine CTCs in appendiceal tumors. We performed a prospective cohort study of consecutive patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy between 2015 and 2019 at a HIPEC referral center. In total, 31 patients were included in the analysis, and circulating tumor cells were detected in 15 patients (48%). CTC positivity was not associated with overall or recurrence-free survival, nor was it correlated with PCI score or histopathological grading. Surprisingly, however, CTCs were found in almost half the patients. The presence or quantities of these cells did not, on their own, predict systemic metastatic potential during the observed time, and they did not appear to significantly correlate with the oncological outcomes recorded.

High-Grade Appendiceal Mucinous Neoplasm Mimicking Appendiceal Tubulovillous Adenoma: A Case Report and Literature Review.

High-grade appendiceal mucinous neoplasm (HAMN) has been separated from appendiceal adenocarcinoma recently as an independent entity and categorized into appendiceal mucinous neoplasms. These neoplasms demonstrate distinct histological characteristics, including architectures and appendiceal mural changes similar to low-grade appendiceal mucinous neoplasm but with high-grade cytology, and no infiltrative invasion. Overt mucinous feature are not evident in some cases as the high-grade neoplastic epithelium may show intracytoplasmic mucin reduction. Occasionally, the neoplastic epithelial cells show florid proliferation and tubulovillous configuration and may be misdiagnosed as appendiceal tubulovillous adenoma. We report the case of a 67-year-old woman with appendicular dilatation and luminal mucin. She underwent an ileocecoectomy. The appendiceal lesion was found histologically to be a HAMN, which closely resembled appendiceal tubulovillous adenoma. The tumor cells demonstrated wild-type p53 expression and mismatch repair proficiency by immunochemistry. Molecular testing showed 1 KRAS mutation, 2 PIK3CA mutations, and 1 BRCA2, EP300, TGFBR2, CHD4, CREBBP, FANCC, PKHD1 mutation each in the tumor. The patient was followed up for 1 year with no evidence of disease.

Long-term outcomes and survival analysis of cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy in patients with pseudomyxoma peritonei at a newly established peritoneal malignancy centre in Japan.

Background: Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is established in the management of pseudomyxoma peritonei (PMP), selected cases of peritoneal mesothelioma, and resectable colorectal or ovarian peritoneal metastases in Western countries. However, the efficacy and feasibility of these techniques are not well established in the Asian population, and little has been reported on long-term survival outcomes for surgically resected PMP patients. Materials and Methods: Retrospective analysis of a prospective database of short- and longer-term outcomes of consecutive patients who underwent CRS and HIPEC for PMP in a newly established peritoneal malignancy unit in Japan between 2010 and 2016. Results: A total of 105 patients underwent CRS and HIPEC and 57 maximal tumor debulking (MTD) for pseudomyxoma peritonei. In the CRS group, the primary tumor was appendiceal in 94 patients (90%) followed by ovarian and colorectal. Major postoperative complications occurred in 22/105 patients (21%) with one in-hospital mortality (0.9%). The 5-year overall and disease-free survival rates for the CRS group were 74.2% and 50.1%, respectively. Multivariate analysis revealed unfavorable histology to be the significant predictor of reduced overall and disease-free survival. Completeness of cytoreduction, CA19-9, and CA125 were also associated with disease-free survival. Conclusions: This is the first report on long-term outcomes and survival analysis of CRS and HIPEC for PMP in the Asian population. CRS and HIPEC can be conducted with reasonable safety and favorable survival in a new center. Complete tumor removal and histological type are the strongest prognostic factors for both overall and disease-free survival.

Actinomycosis as a rare cause of acute appendicitis: Case report and comprehensive literature review.

INTRODUCTION AND IMPORTANCE: Actinomycosis is a rare, chronic bacterial infection caused by Actinomyces species. While it commonly affects the cervicofacial region, thorax, and abdomen, appendicular involvement is extremely uncommon. This case report details the presentation, diagnosis, and management of a 45-year-old female patient with acute appendicitis secondary to actinomycosis. CASE PRESENTATION: A 45-year-old woman, with an 8-year intrauterine device history, presented with three-day right iliac fossa pain, vomiting, and stable vital signs. Laboratory tests revealed an inflammatory syndrome. Suspecting acute appendicitis, a CT scan confirmed a swollen 10 mm appendix. Laparoscopic surgery revealed a phlegmonous appendix, leading to an uncomplicated appendectomy. Pathological examination confirmed actinomycotic granules, supporting the diagnosis of actinomycosis appendicitis. The patient received 18 million units of intravenous penicillin G daily for 6 weeks followed by a 6-month course of oral amoxicillin (1 g three times daily) thereafter, showing favorable progression with no symptoms. Normal clinical and ultrasound follow-ups were observed at one year. CLINICAL DISCUSSION: Appendiceal actinomycosis is a rare condition. Women, especially those with intrauterine contraceptives, experience an increase in cases due to chronic inflammation. Typically underdiagnosed, actinomycosis mimics other conditions, presenting with nonspecific symptoms. Laboratory results offer limited assistance, and histological confirmation is crucial. Histopathological examination is mandatory for diagnosis confirmation. Management involves surgical resection and prolonged penicillin-based antibiotics, providing a favorable prognosis with low mortality. CONCLUSION: This case underscores the importance of considering rare etiologies, such as actinomycosis, in the differential diagnosis of appendicitis. Timely recognition and management are crucial for optimal patient outcomes.