Challenging Diagnosis of Abdominal Actinomycosis: A Case Report of a 59-Year-Old Male With Acute Appendicitis-Like Presentation.

Abdominal actinomycosis, a rare and often misdiagnosed condition caused by Actinomyces israelii, typically a commensal organism in the oral cavity and gastrointestinal tract, can become pathogenic, leading to chronic granulomatous infections that mimic various abdominal pathologies, including malignancies. We present a case of a 59-year-old male with coronary artery disease and type 2 diabetes who presented with severe abdominal pain, initially diagnosed as acute appendicitis. During exploratory laparotomy, an ileocecal band mimicking a congenital anomaly was discovered. Histopathological examination confirmed abdominal actinomycosis, revealing clusters of Actinomyces bacteria surrounded by acute inflammatory cells. The patient was successfully treated with surgical intervention and prolonged penicillin therapy, with no recurrence during a four-month follow-up. This case highlights the diagnostic challenges posed by abdominal actinomycosis and emphasizes the importance of considering it in the differential diagnosis of abdominal masses and appendicitis-like symptoms.

Cryptogenic HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella) CNS Abscess in an Otherwise Healthy Patient With a Patent Foramen Ovale.

Actinomyces and HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella) organisms are part of the oral microbiome and rarely affect the central nervous system (CNS). CNS infections with these agents can be caused by contiguous or hematogenous spread. We present a case of a 25-year-old immunocompetent male who presented with a one-week history of progressively worsening generalized headaches, photophobia, nausea, and vomiting. Despite a normal physical exam and the absence of leukocytosis, head imaging showed a right frontal lobe abscess. The patient was started empirically on vancomycin, ceftriaxone, and metronidazole, and surgery was performed. Surgical cultures grew organisms from the HACEK spectrum (Aggregatibacter, Eikenella), Gemella morbillorum, Streptococcus constellatus, and Actinomyces georgiae. Serial imaging studies showed a rapid increase in the size of the residual abscess, and the patient needed repeat intervention within five days. He was discharged five days after the repeat surgery on IV therapy prior to the transition to oral antibiotics. While the patient was found to have a small patent foramen ovale, there was no evidence of bacteremia or valvular vegetation, and no evidence of dental or sinus disease was seen on imaging. This case suggests that even in the absence of any clear sources of infection, cryptogenic brain abscesses can still occur sporadically in young, healthy patients.

Microbiology of Actinomyces Species Isolated From Patients With Invasive Disease and Contaminated Samples in a Comprehensive Cancer Center.

Background: Actinomyces are mucous membrane commensals that infrequently cause invasive disease. Our goal was to define Actinomyces species prevalence, the predominant disease site and risk factors for actinomycosis. Methods: We retrospectively reviewed patients with growth of Actinomyces species from cultures in a single-cancer center from July 2007 to June 2020. Proven invasive actinomycosis was defined as the presence of compatible clinical syndrome and radiographic findings with histopathological confirmation or culture from a normally sterile site. Probable invasive actinomycosis was defined based on the same criteria but without histologic confirmation. Contaminants were defined as culture growth in the absence of clinical or radiological findings consistent with disease. Speciation of Actinomyces was performed by the bioMerieux VITEK 2 anaerobic and coryneform identification card. Results: Of 235 patients, 179 (76.2%) had malignancy. Among 90 (38.3%) patients with invasive actinomycosis, A odontolyticus was isolated in 32 (35.6%), followed by A meyeri in 20 (22.2%), and A naeslundii in 17 (18.9%). Among 145 (61.7%) colonized patients, A odontolyticus was isolated in 67 (46.2%), followed by A naeslundii in 27 (18.6%). Abdominopelvic infection was the most common site for invasive actinomycosis documented in 54 patients (60.0%) followed by orocervicofacial in 14 (15.6%) and thoracic in 10 (11.1%). Conclusions: A odontolyticus, A meyeri, and A naeslundi were the most frequently isolated species causing invasive actinomycosis, and A odontolyticus and A nauslendii among colonizers. Abdominopelvic represented the most frequent site for invasive disease. Further studies are needed to investigate the epidemiology of Actinomyces species in this population.

Disseminated Actinomyces Case Report: A Mimicker of Advanced Ovarian Malignancy.

Introduction: Disseminated actinomyces is a rare infection that presents with subtle symptoms and radiographic findings. Patients frequently complain of pelvic pain and nonspecific gastrointestinal symptoms. Imaging can reveal a tumor-like mass and mimic malignancy. Here we discuss a patient who presented with abdominal pain, and computerized tomography (CT) imaging revealed a pelvic mass and features suggestive of carcinomatosis concerning for ovarian cancer. Case Presentation: A 55-year-old woman presented with 1 week of abdominal pain and 5 months of increasing abdominal girth. CT imaging was concerning for an advanced ovarian cancer and demonstrated a pelvic mass, peritoneal nodularity, and omental thickening. She subsequently underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy and abdominal washout with pathology and cultures revealing disseminated actinomyces. She fully recovered after receiving a long course of antibiotics. Conclusion: This case adds to the limited literature illustrating that disseminated actinomyces can present similarly to ovarian cancer. The diagnosis may only be elucidated upon histologic examination of surgical specimens. Consideration of pelvic actinomyces should be entertained in all women presenting with pelvic tumors on imaging and intrauterine devices in place.

Case Report: Acute large bowel obstruction with actinomycosis of the sigmoid colon mimicking neoplasm.

Introduction: Actinomycosis is an uncommon inflammatory bacterial disease caused by Actinomyces species, especially Actinomyces Israeli. Abdominopelvic forms are relatively rare and may involve the colon as a solid mass, mimicking a malignant tumor. Case presentation: A 68-year-old Tunisian man, with a history of diabetes, hypertension, penicillin allergy, and renal failure, presented to the emergency department with abdominal pain, vomiting, and bowel obstruction. CT scan showed an acute intestinal obstruction upstream with obstructive tissular mass at the sigmoid colon. Emergency surgery revealed a sigmoid mass and a pre-perforative cecum. Total colectomy was performed, with ileostomy and distal end closure. Histological examination confirmed Actinomyces infection. The patient was then placed on long-term doxycycline and Bactrim, with no recurrence over a 9-month follow-up period. Conclusion: Abdominal actinomycosis, though rare, presents diagnostic challenges. It can be mistaken for malignancy, leading to unnecessary surgery in non-complicated cases, since it is effectively treated by antibiotics. In complicated cases, a combined approach involving both surgery and antibiotic therapy is necessary until the infection is completely eradicated.

Prevalence of Helicobacter pylori in routine adult tonsillectomies.

Helicobacter pylori, a curved bacterial rod and causative agent of peptic ulcer and gastric adenocarcinoma, is found as an infectious agent in the stomach of over half of the global population. H. pylori has been identified in oral biofilms and its presence in adenotonsillar tissues has been suggested, with variations in testing methodology both proving and disproving its presence. The current study employed 119 formalin-fixed paraffin-embedded tonsillar tissues from an adult population (n=86) in a major metropolitan city with immunohistochemistry procedures using a monoclonal antibody to determine the incidence of H. pylori in the tonsils. H. pylori was identified in 72.1% of the patients and was associated with Actinomyces spp. in 92.0% of those cases. The high incidence of H. pylori in patients undergoing tonsillectomy suggests that H. pylori may be a contributing factor for tonsillitis and tonsillar hypertrophy. Furthermore, the reservoir for H. pylori in the tonsils may explain why some persons remain refractory to antibiotic treatment for gastric H. pylori.

Abdominal actinomycosis presented as acute abdomen with intra-abdominal multiple tumors: A case report.

INTRODUCTION AND IMPORTANCE: Actinomycosis, a rare infection caused by Actinomyces spp., typically presents as a chronic condition affecting various regions, particularly the cervicofacial, thoracic, and abdominal areas. Its diagnosis is often difficult due to symptom overlap with malignancies and other infections. This report details a case of abdominal actinomycosis mimicking multiple intra-abdominal tumors, complicating diagnosis and treatment. CASE PRESENTATION: A 67-year-old male with uncontrolled type 2 diabetes presented with generalized abdominal pain, nausea, vomiting, constipation, and significant weight loss. Physical examination revealed distention and severe abdominal tenderness. Laboratory tests showed leukocytosis and anemia. Diagnostic laparotomy revealed multiple intra-abdominal tumors. Histopathology confirmed actinomycosis without malignancy or tuberculosis. Intravenous amoxicillin was started; however, the patient discharged himself against medical advice after two days due to personal reasons unrelated to his treatment plan. He returned three months later with persistent abdominal pain and additional hepatic lesions. Extended antibiotic therapy for 12 months led to the resolution of symptoms during follow-up. CLINICAL DISCUSSION: Abdominal actinomycosis is rare and often associated with conditions like diabetes. This case underscores the infection's potential to mimic malignancy and highlights the need for considering actinomycosis in differential diagnoses of acute abdomen, especially in immunocompromised patients. The patient's uncontrolled diabetes likely contributed to the infection's development and spread. CONCLUSION: Abdominal actinomycosis can present acutely, mimicking neoplastic diseases with multiple intra-abdominal masses. Early recognition and prolonged antibiotic therapy are essential to prevent systemic spread, especially in immunocompromised individuals. Clinicians should consider actinomycosis in patients with poorly controlled diabetes and abdominal symptoms.

Molecular basis for sortase-catalyzed pilus tip assembly.

During pilus assembly within the Gram-positive bacterial envelope, membrane-bound sortase enzymes sequentially crosslink specific pilus protein monomers through their cell wall sorting signals (CWSS), starting with a designated tip pilin, followed by the shaft made of another pilin, ultimately anchoring the fiber base pilin to the cell wall. To date, the molecular determinants that govern pilus tip assembly and the underlying mechanism remain unknown. Here, we addressed this in the model organism Actinomyces oris. This oral microbe assembles a pathogenically important pilus (known as type 2 fimbria) whose shafts, made of FimA pilins, display one of two alternate tip pilins-FimB or the coaggregation factor CafA-that share a markedly similar CWSS. We demonstrate that swapping the CWSS of CafA with that of FimB produces a functional hybrid, which localizes at the pilus tip and mediates polymicrobial coaggregation, whereas alanine-substitution of the conserved FLIAG motif within the CWSS hampers these processes. Remarkably, swapping the CWSS of the normal cell wall-anchored glycoprotein GspA with that of CafA promotes the assembly of hybrid GspA at the FimA pilus tip. Finally, exchanging the CWSS of the Corynebacterium diphtheriae shaft pilin SpaA with that of CafA leads to the FLIAG motif-dependent localization of the heterologous pilus protein SpaA at the FimA pilus tip in A. oris. Evidently, the CWSS and the FLIAG motif of CafA are both necessary and sufficient for its destination to the cognate pilus tip specifically assembled by a designated sortase in the organism. IMPORTANCE: Gram-positive pili, whose precursors harbor a cell wall sorting signal (CWSS) needed for sortase-mediated pilus assembly, typically comprise a pilus shaft and a tip adhesin. How a pilin becomes a pilus tip, nevertheless, remains undetermined. We demonstrate here in Actinomyces oris that the CWSS of the tip pilin CafA is necessary and sufficient to promote pilus tip assembly, and this functional assembly involves a conserved FLIAG motif within the CWSS. This is evidenced by the fact that an A. oris cell-wall anchored glycoprotein, GspA, or a heterologous shaft pilin from Corynebacterium diphtheriae, SpaA, engineered to have the CWSS of CafA in place of their CWSS, localizes at the pilus tip in a process that requires the FLIAG motif. Our findings provide the molecular basis for sortase-catalyzed pilus tip assembly that is very likely employed by other Gram-positive bacteria and potential bioengineering applications to display antigens at controlled surface distance.

Mimicry of Rhabdomyosarcoma by Tonsillar Actinomycosis: Case Report.

Actinomycosis is a rare infectious disease characterized by slowly progressive, chronic suppurative lesions, often mistaken for malignancies due to its ability to mimic them. It is caused by Actinomyces bacteria, which are part of the normal flora of the human oropharynx, gastrointestinal, and urogenital tracts. This case report describes a 51-year-old male with a history of mandibular rhabdomyosarcoma presenting with severe shoulder and hip pain, dysphagia, and headaches, initially suspected to be a cancer recurrence. However, after further investigation, including a PET-CT and tonsillectomy, the diagnosis of actinomycosis was confirmed through histopathological examination. The case highlights the diagnostic challenges of actinomycosis, especially in patients with complex clinical histories, emphasizing the importance of considering it as a differential diagnosis in similar presentations. The patient was treated with long-term antibiotic therapy, predominantly beta-lactams, demonstrating the necessity of a comprehensive diagnostic approach and the implications of a delayed diagnosis. This case underscores the critical need for high clinical suspicion and awareness among healthcare professionals regarding the potential for actinomycosis to mimic more common diseases, ensuring timely and accurate treatment.

Pulmonary mediastinal actinomycosis with "pound cake sign" on magnetic resonance imaging mimicking an infiltrative malignant tumor: A case report.

Actinomycosis is a rare chronic suppurative granulomatous disease. Surgical biopsy is often performed in patients with chest actinomycosis because malignancy is suspected in most cases. A 62-year-old man presented to our hospital with fever and exertional dyspnea that had persisted for several months. Contrast-enhanced computed tomography showed an irregularly shaped mass with contrast enhancement in the anterior mediastinum and consolidation in the left upper lung lobe contiguous with this mass, as well as multiple nodules in both lungs. The pulmonary artery trunk was stenotic and surrounded by the mass, and the right heart system was enlarged. Thoracoscopic biopsy was performed but failed to yield a diagnosis. Contrast-enhanced computed tomography after one month revealed an increased mass and worsening right heart strain. 18F-FDG (fluorodeoxyglucose) positron emission tomography/computed tomography and contrast-enhanced magnetic resonance imaging also suggested a malignant tumor, and an open chest biopsy was performed. No malignant cells were identified and actinomycetes were detected by histopathology and bacterial culture. The patient was treated with antibiotics, following which his contrast-enhanced computed tomography findings and general condition improved.

Tracheoesophageal fistula due to Candida and Actinomyces co-infection: A case report and comprehensive review of the literature.

Acquired benign tracheoesophageal fistulas and bronchoesophageal fistulas (TEF) are typically associated with granulomatous mediastinal infections, 75% of which are iatrogenic. Candida albicans and Actinomyces are commonly occurring organisms, but are uncommon etiologies of TEF. Normal colonization and the slow growth characteristics of some species of these agents rarely result in infection, mycetoma, and broncholithiasis, and thus, delays in diagnosis and treatment are likely. Few reports describe C. albicans or Actinomyces spp. as the etiology of TEF or broncholithiasis. Herein, we report a case of benign acquired TEF secondary to coinfection of Candida and Actinomyces complicated by the formation of an actinomycetoma and broncholithiasis and a comprehensive literature review to highlight the unique nature of this presentation and offer a diagnostic algorithm for diagnosis and treatment of TEFs. Following a presentation of three months of productive cough, choking sensation, night sweats, and weight loss, a bronchoscopy revealed a fistulous connection between the esophagus and the posterior right middle lobe. Pathology identified a calcified fungus ball and a broncholith secondary to the co-infection of Candida and Actinomyces. This unique presentation of Candida and Actinomyces co-infection and the associated diagnostic algorithm are presented as education and a useful tool for clinicians.

Extranodal Natural Killer/T-cell Lymphoma, Nasal Type Occurring After Actinomyces Infection: A Case Report.

The pathogenesis of extranodal natural killer/T-cell lymphoma (ENKTL) remains largely unknown. Herein, we present a case of ENKTL that may have occurred during the treatment of Actinomyces infection. A 69-year-old woman was admitted to our hospital with nasal bleeding, and a nasopharyngeal mass was observed. The patient was diagnosed with Actinomyces infection on biopsy, and oral antibiotics were administered. The tumor decreased in size; however, swelling of the nasal mucosa and perforation of the nasal septum were observed. A biopsy revealed a recurrence of Actinomyces infection, and oral antibiotics were again administered. The mucosal swelling improved temporarily, but the condition gradually deteriorated. The patient was diagnosed with ENKTL based on a third biopsy. Retrospective evaluation of the biopsies showed that there were no CD56-positive cells in the first specimen; however, the number of CD56-positive cells gradually increased in the second and third specimens. We retrospectively observed the occurrence of ENKTL under chronic inflammatory conditions due to Actinomyces infection in this case. In addition, this case suggests that the possibility of malignancy must be considered when managing such patients with Actinomyces infection.

Giant pulmonary artery aneurysm associated with SARS-CoV-2 infection and Actinomyces odontolyticus sepsis: A case report.

Giant septic pulmonary artery aneurysms (PAAs) are rare but important entities, with few cases having been reported worldwide. Early diagnosis and prompt treatment are crucial in the management of such cases. We report a 56-year-old female patient presenting with fatigue, nausea and vomiting who was first diagnosed with diabetic ketoacidosis (DKA) and developed life-threatening giant infectious PAA secondary to SARS-CoV-2 infection and Actinomyces odontolyticus sepsis. The patient did not develop any specific symptoms, and enhanced computed tomography (CT) revealed a massive PAA of 5.6 × 4.9 cm in size at the left pulmonary hilar with normal pulmonary artery (PA) pressures. After multidisciplinary discussion and after considering the critical condition accompanied by sepsis increased the risk of surgery, endovascular treatment was the first therapy of choice for the patient; nevertheless, the patient ultimately opted for hospice care. This case report aims to raise awareness of PAAs, which are rare but potentially fatal complications of infectious diseases such as COVID-19 pneumonia and Actinomyces odontolyticus sepsis.

The "Lumpy Jaw" Disease-Treatment and Diagnostical Challenge of Actinomycotic Osteomyelitis.

Background: Osteomyelitis is a serious entity that can occur in many different locations. Especially in the mandible, osteomyelitis can show different clinical courses, which differ clearly from other anatomical regions in terms of severity and treatment. Osteomyelitis in the mandible is often caused by mixed species of the oral cavity. A species causing subacute/chronic osteomyelitis can be actinomyces. Actinomycotic osteomyelitis of the jaw represents a diagnostic and treatment challenging disease. Conclusion: This article describes our perspective on the therapy pillars treating actinomycotic osteomyelitis. The rapid introduction of the two therapeutic elements (antibiosis/surgical therapy) is crucial regarding the outcome of this entity.

Molecular basis for dual functions in pilus assembly modulated by the lid of a pilus-specific sortase.

The biphasic assembly of Gram-positive pili begins with the covalent polymerization of distinct pilins catalyzed by a pilus-specific sortase, followed by the cell wall anchoring of the resulting polymers mediated by the housekeeping sortase. In Actinomyces oris, the pilus-specific sortase SrtC2 not only polymerizes FimA pilins to assemble type 2 fimbriae with CafA at the tip, but it can also act as the anchoring sortase, linking both FimA polymers and SrtC1-catalyzed FimP polymers (type 1 fimbriae) to peptidoglycan when the housekeeping sortase SrtA is inactive. To date, the structure-function determinants governing the unique substrate specificity and dual enzymatic activity of SrtC2 have not been illuminated. Here, we present the crystal structure of SrtC2 solved to 2.10-Å resolution. SrtC2 harbors a canonical sortase fold and a lid typical for class C sortases and additional features specific to SrtC2. Structural, biochemical, and mutational analyses of SrtC2 reveal that the extended lid of SrtC2 modulates its dual activity. Specifically, we demonstrate that the polymerizing activity of SrtC2 is still maintained by alanine-substitution, partial deletion, and replacement of the SrtC2 lid with the SrtC1 lid. Strikingly, pilus incorporation of CafA is significantly reduced by these mutations, leading to compromised polymicrobial interactions mediated by CafA. In a srtA mutant, the partial deletion of the SrtC2 lid reduces surface anchoring of FimP polymers, and the lid-swapping mutation enhances this process, while both mutations diminish surface anchoring of FimA pili. Evidently, the extended lid of SrtC2 enables the enzyme the cell wall-anchoring activity in a substrate-selective fashion.

Tongue-Coating Microbial and Metabolic Characteristics in Halitosis.

Halitosis is a common oral condition, which leads to social embarrassment and affects quality of life. Cumulative evidence has suggested the association of tongue-coating microbiome with the development of intraoral halitosis. The dynamic variations of tongue-coating microbiota and metabolites in halitosis have not been fully elucidated. Therefore, the present study aimed to determine the tongue-coating microbial and metabolic characteristics in halitosis subjects without other oral diseases using metagenomics and metabolomics analysis. The participants underwent oral examination, halitosis assessment, and tongue-coating sample collection for the microbiome and metabolome analysis. It was found that the microbiota richness and diversity were significantly elevated in the halitosis group. Furthermore, species from Actinomyces, Prevotella, Veillonella, and Solobacterium were significantly more abundant in the halitosis group. However, the Rothia and Streptococcus species exhibited opposite tendencies. Eleven Kyoto Encyclopedia of Genes and Genomes pathways were significantly enriched in the halitosis tongue coatings, including cysteine and methionine metabolism. Functional genes related to sulfur, indole, skatole, and cadaverine metabolic processes (such as serA, metH, metK and dsrAB) were identified to be more abundant in the halitosis samples. The metabolome analysis revealed that indole-3-acetic, ornithine, and L-tryptophan were significantly elevated in the halitosis samples. Furthermore, it was observed that the values of volatile sulfur compounds and indole-3-acetic abundances were positively correlated. The multiomics analysis identified the metagenomic and metabolomic characteristics to differentiate halitosis from healthy individuals using the least absolute shrinkage and selection operator logistic regression and random forest classifier. A total of 19 species and 39 metabolites were identified as features in halitosis patients, which included indole-3-acetic acid, Bacillus altitudinis, Candidatus Saccharibacteria, and Actinomyces species. In conclusion, an evident shift in microbiome and metabolome characteristics was observed in the halitosis tongue coating, which may have a potential etiological significance and provide novel insights into the mechanism for halitosis.

Detection of pulmonary actinomycosis by metagenomic next-generation sequencing in a cancer patient receiving maintenance olaparib: A review and case report.

A 52-year-old female patient receiving olaparib maintenance treatment was admitted to hospital with a low fever and chest tightness. A CT scan of the patient's chest showed diffuse ground glass shadow or miliary nodular shadow in the bilateral lungs. Her inflammatory biomarkers were almost normal, except the slightly elevated C-reactive protein. Moreover, lymphocytes count obviously decreased. Empirical treatment did not relieve her symptoms, while traditional testing developed negative results. The results of metagenomic next-generation sequencing (mNGS) revealed the presence of a potential pathogen, Actinomyces odontolyticus (A. odontolyticus), in bronchoalveolar lavage fluid (BLAF). Once large-dosed penicillin G was administered, the fever returned to normal and chest tightness disappeared. Reexamination of chest CT revealed that the pulmonary lesions was almost absorbed. Our case demonstrated that mNGS is a novel approach to identify pathogens sensitively and accurately, especially for uncommon and atypical infection.

An overview of case reports and case series of pulmonary actinomycosis mimicking lung cancer: a scoping review.

Background: Pulmonary actinomycosis (PA) is a rare type of Actinomyces infection that can be challenging to diagnose since it often mimics lung cancer. Methods: Published case reports and case series of PA in patients with suspicion of lung cancer were considered, and data were extracted by a structured search through PubMed/Medline. Results: After analyzing Medline, 31 studies were reviewed, from which 48 cases were extracted. Europe had the highest prevalence of reported cases with 45.1%, followed by Asia (32.2%), America (19.3%), and Africa (3.2%). The average age of patients was 58.9 years, and 75% of all patients were above 50 years old. Male patients (70%) were predominantly affected by PA. The overall mortality rate was 6.25%. In only eight cases, the causative agent was reported, and Actinomyces odontolyticus was the most common isolated pathogen with three cases. Based on histopathological examination, 75% of the cases were diagnosed, and the lobectomy was performed in 10 cases, the most common surgical intervention. In 50% of the cases, the selective antibiotics were intravenous and oral penicillin, followed by amoxicillin (29.1%), amoxicillin-clavulanic acid, ampicillin, levofloxacin, and doxycycline. Conclusion: The non-specific symptoms resemble lung cancer, leading to confusion between PA and cancer in imaging scans. Radiological techniques are helpful but have limitations that can lead to unnecessary surgeries when confusing PA with lung cancer. Therefore, it is important to raise awareness about the signs and symptoms of PA and lung cancer to prevent undesirable complications and ensure appropriate treatment measures are taken.

Actinomycosis of the Middle Ear Mimicking Cholesteatoma: A Case Report and Literature Review.

Actinomycosis is a rare infection of the middle ear. Actinomyces is an anaerobic, filamentous bacterium causing granuloma formation and suppurative infection. We present a young male with a nine-month history of unilateral, yellow-coloured otorrhoea and hearing loss. Swabs showed no growth, with the infection not responding to oral or topical antibiotics. Computed tomography of temporal bones was consistent with cholesteatoma and ossicular disruption. Surgical exploration revealed a yellow, cystic mass within the middle ear. Cortical mastoidectomy and washout were performed. Histological diagnosis confirmed Actinomyces clusters with positive gram stain. Actinomycosis of the middle ear typically presents as chronic otitis media. It likely reaches the middle ear via the eustachian tube. It is often misdiagnosed due to culture insensitivity; however, clinical suspicion can aid labs in providing an optimum culture environment. Tympanomastoidectomy allows for histopathological diagnosis. Surgical resection should be followed by a prolonged course of antibiotics.

Appendiceal actinomycosis mimicking malignant tumor: a rare case report.

Introduction: Actinomycosis is an uncommon bacterial infection caused by Actinomyces bacteria that typically progresses slowly and leads to the formation of masses. Although it commonly affects the cervicofacial area, about 20% of cases occur in the abdominopelvic region. Because the disease can be mistaken for a tumour due to its infiltrative mass-like nature on imaging, over 90% of cases are only diagnosed following surgery and histological confirmation. This report describes a case of an appendicular mass, initially suspected to be a malignant tumour, but eventually diagnosed as appendiceal actinomycosis. Presentation of case: Upon initial presentation, a 53-year-old woman with type II diabetes mellitus and no prior surgical history, displayed abnormal appendiceal uptake during a PET-computed tomography (CT) scan conducted for a suspected spinal tumour. Colonoscopy did not indicate any notable observations, and the patient chose to defer immediate action. Several months later, a CT scan revealed an increased mass-like appearance of the appendix compared to the previous PET-CT scan. After multidisciplinary discussions, a right laparoscopic hemicolectomy was recommended due to suspected malignancy. However, histological staining on microscopy confirmed actinomycosis originating from the appendix. Discussion: Chronic appendicitis with radiologic features similar to appendiceal carcinoma, or abdominal masses located in the ileocecal area, in patients with or without a previous surgical history should raise suspicion of actinomycosis. Conclusion: Appendiceal actinomycosis should be considered in the differential diagnosis in the aetiology of chronic appendicitis mimicking appendiceal carcinoma. Awareness and accurate diagnosis of appendiceal actinomycosis can prevent unnecessary extended surgery as was performed in this case.