[Imaging of actinomycosis: CT scan, bronchial embolization and pathology]. / Imageries d'une actinomycose : scanner, embolisation bronchique et anatomopathologie.

Pulmonary actinomycosis is a rare infectious disease that can be difficult to diagnose due to nonspecific imaging abnormalities and to a need for repeated lung sampling by CT-guided biopsy or bronchoscopy. It may present with hemoptysis, which can occur with or without antibiotic therapy and bronchial artery embolization may be required. We report here a case of pulmonary actinomycosis with imaging by thoracic CT, digital subtraction angiography, and pathological specimens.

Pericardial actinomycosis.

A man in his 50s, with a history of night sweats and weight loss, presented acutely with dyspnoea and chest pain. Imaging revealed right middle lobe consolidation and a large pericardial effusion. The diagnosis of actinomycosis was made using endobronchial ultrasound-guided sampling from the pericardial effusion. An orthopantomogram demonstrated that the source was a large cavity in the left lower wisdom tooth. This tooth was extracted before the completion of his antibiotic course, and the patient made a full recovery. Cardiac actinomycosis is rare, and there are few case reports describing endobronchial ultrasound-guided sampling of pericardial fluid.

A 13-Year-Old Boy with Chest Wall Actinomycosis Mimicking Ewing Sarcoma on Imaging.

BACKGROUND Actinomyces, a filamentous, branching, anaerobic gram-positive bacillus, typically found as a commensal organism in the oral cavity, can lead to rare chronic bacterial infections in various anatomical regions. Chest wall involvement represents an uncommon presentation, posing significant diagnostic challenges. This report focuses on the case of a 13-year-old boy presenting with chest wall actinomycetoma that closely resembled Ewing sarcoma on imaging. CASE REPORT We present the case of a 13-year-old male with no previous medical history who presented to the Emergency Department with progressive left-sided chest pain following a sports-related fall. Physical examination revealed mild swelling and tenderness on the left anterior chest wall. A chest computed tomography (CT) scan revealed a large tumor involving the lower left chest wall, suggesting Ewing sarcoma. However, a histopathological examination unexpectedly confirmed actinomycosis of the chest wall. Intravenous penicillin G was promptly initiated for 4 weeks. A follow-up CT scan after 4 weeks of therapy demonstrated a significant response with notable reduction in the size of the chest wall mass. The patient then continued with maintenance therapy using oral amoxicillin for 12 months. Throughout this period, complete resolution of the chest wall mass occurred, with no significant adverse events or complications observed. CONCLUSIONS This case highlights the importance of considering uncommon differential diagnoses like chest wall actinomycosis in patients presenting with chest wall masses. The diagnostic complexities associated with this rare condition emphasize the need for a comprehensive evaluation strategy, incorporating histopathological examination and imaging.

Extensive actinomycosis with intracranial and mediastinal involvement: a therapeutic challenge.

Central nervous system (CNS) involvement by actinomycosis is rare, seen in 2%-3% cases. It mostly spreads to CNS by haematogenous route from a distant primary site such as oral cavity, lung, abdomen or pelvis. Direct CNS extension can also occur. It mostly presents as brain abscess, meningoencephalitis, actinomycetoma, subdural empyema and epidural abscess. We report one case of extensive actinomycosis having intra and extraparenchymal CNS, spinal canal, retropharyngeal and mediastinal involvement. Due to such widespread extension and involvement of vital areas, complete surgical debulking was not possible. In addition to therapeutic resistance to conventional antibiotics, repetitive negative cultures posed significant difficulty in the case management.

Thoracoabdominal actinomycosis associated with laparoscopic cholecystectomy and mimicking metastatic pulmonary malignancy.

Actinomyces naeslundii is rarely isolated in cases of actinomycosis. We present a case of thoracoabdominal actinomycosis caused by inadvertent enterotomy and gallstone spillage during a laparoscopic cholecystectomy. The actinomycosis initially presented as recurrent episodes of pneumonia, shortness of breath and unintentional weight loss. Initial CT imaging demonstrated pleural thickening along the right lung base as well as ill-defined consolidation in the right lower lobe. Repeat CT imaging showed progression of the mass-like region of consolidation with extrapulmonary spread to involve the abdomen, retroperitoneum and retrohepatic areas. Treatment involved intravenous antibiotics with concurrent abscess drainage followed by oral antibiotics.

Pulmonary actinomycosis mimicking lung cancer on 18F-fluorodeoxyglucose positron emission tomography: a case report.

BACKGROUND: Pulmonary actinomycosis is a chronic disease characterized by abscess formation, draining sinuses, fistulae, and tissue fibrosis. It can mimic other conditions, particularly malignant and granulomatous diseases, and is perhaps extremely challenging to diagnose. CASE PRESENTATION: A 64-year-old Japanese man presented with 6-week history of a painful solid lump in the chest wall. Chest computed tomography scan revealed a mass-like consolidation in the left upper lobe, with rib erosion and direct extension into the anterior chest wall. 18F-fluorodeoxyglucose positron emission tomography scan showed increased metabolic activity in the mass, which is indicative of primary lung cancer. The bronchoscopy and computed tomography scan-guided transthoracic biopsy results were considered nondiagnostic. Finally, the patient was diagnosed with pulmonary actinomycosis via surgical resection. He completed an 8-week course of antibiotic therapy and experienced no recurrence. CONCLUSIONS: There is no difference in positron emission tomography/computed tomography scan findings between actinomycosis and malignancy. Therefore, pulmonary actinomycosis should be considered in the differential diagnosis of cases involving intensive activity on 18F-fluorodeoxyglucose positron emission tomography scan.

Clinical and radiological characteristics of pulmonary actinomycosis mimicking lung malignancy.

INTRODUCTION: Pulmonary actinomycosis, clinically and radiologically, mimics abscess, tuberculosis, and lung malignancy, resulting in misdiagnosis or delay in diagnosis. In this study, we analyzed the clinicoradiological features of pulmonary actinomycosis, the presence of any differences between clinical prediagnosis and radiological diagnosis, and whether imaging modalities help distinguish pulmonary actinomycosis from lung cancer. METHODS: A total of 22 patients who had a histopathological diagnosis of actinomycosis in a tertiary health center participated in this study. Of these, 14 had positron-emission tomography/computed tomography. RESULTS: In all, 81.8% of the patients were males. The diagnostic procedures employed for the diagnosis of actinomycosis were surgery in 54.5% of patients, fiberoptic bronchoscopy in 36.4% of patients, and rigid bronchoscopy in 9.1% of patients. Radiological and clinical prediagnosis showed malignancy in 31.8 and 40.9% of patients, respectively. The mean of the maximum standardized uptake value was 6.33±3.6 on positron-emission tomography/computed tomography. Kappa compliance analysis revealed that clinical and radiological diagnoses were significantly compatible with each other and that radiological pre-diagnoses were not superior to clinical diagnoses (κ=0.701 and p<0.001). CONCLUSION: Pulmonary actinomycosis shows high metabolic uptake in positron-emission tomography/computed tomography, and this may mislead clinicians for a diagnosis of malignancy. Our results suggest that positron-emission tomography/computed tomography does not help distinguish pulmonary actinomycosis from lung malignancy and does not provide a clear diagnostic benefit to the clinician, so pathological diagnosis is necessary.

Tonsillar actinomycosis that mimics tonsillar neoplasm.

Actinomycosis is a chronic suppurative infection that can develop almost anywhere in the body. Cervicofacial actinomycosis is the most common form of the disease. We report a case of tonsillar actinomycosis that causes massive, asymmetric enlargement of tonsil and mimics the neoplasia. The most common cause of asymmetric tonsil hypertrophy is tonsillar squamous cell carcinoma and lymphomas. Tonsillar actinomycosis is a rare entity that should be kept in mind, if cases cannot be clarified with clinical and laboratory findings, when radiological findings are suspicious about malignancy.

Infecciones abdominales por Actinomyces odontolyticus: comunicación de dos casos / Abdominal infections due Actinomyces odontolyticus: a report of two cases

Resumen Actinomyces spp es una familia de bacilos grampositivos saprofíticos que rara vez producen infecciones en el ser humano. Actinomyces odontolyticus forma parte de la microbiota oral y existen escasos reportes de casos de infecciones asociadas a este microorganismo, principalmente de localización oral, torácica, pélvica y bacteremias. Estas infecciones se caracterizan por ser recidivantes y causar abscesos y trayectos fistulosos. Su aislamiento microbiológico es difícil ya que la mayoría de los equipos automatizados no identifican la especie de Actinomyces, por lo que técnicas como MALDI-TOF MS resulta de gran ayuda en el diagnóstico definitivo. Finalmente, el tratamiento antibacteriano debe ser prolongado, acompañado del drenaje quirúrgico de las colecciones. Presentamos dos casos de infección abdominal recurrente por A. odontolyticus, en pacientes inmunocompetentes, con tratamiento exitoso.

Abstract Actinomyces spp is a family of saprophytic gram-positive rods that rarely cause infections in humans. Actinomyces odontolyticus is part of the oral microbiota and there are few case reports of infections associated, mainly oral, thoracic, pelvic involvement and bacteremia. These infections are characterized by being recurrent and causing abscesses and fistulous tracts. Microbiological isolation of the microorganism is difficult because most of the automated identification equipment does not detect the Actinomyces species. The use of identification techniques such as MALDI-TOF MS is a great help in the definitive diagnosis. Finally, antibacterial treatment should be prolonged, and accompanied by surgical drainage of the collections. We report two cases of recurrent abdominal infection by A. odontolyticus, in immunocompetent patients, with successful treatment.

Pancreatic actinomycosis treated by antibiotics after diagnosis using endoscopic ultrasound-guided fine-needle biopsy.

A 71-year-old man who had undergone total gastrectomy, partial pancreatectomy, and splenectomy with Roux-en-Y reconstruction for gastric cancer was referred for a possible pancreatic tail tumor. Contrast-enhanced computed tomography showed mold-like, poor contrast lesion in the dilated main pancreatic duct in the pancreatic tail. Endoscopic ultrasonography revealed a slightly hyperechoic solid lesion that occupied the lumen of the main pancreatic duct. Linear calcification was observed in the lesions on both computed tomography and endoscopic ultrasonography, and endoscopic ultrasound-guided fine-needle biopsy was performed. Histopathology revealed sulfur grains and inflammatory infiltrates with no malignant findings. We also performed an anaerobic culture using fine-needle biopsy specimens, and Actinomyces meyeri was detected in the culture results. After confirming susceptibility, oral administration of amoxicillin was initiated. After 8 months of treatment, the size of the lesion slightly decreased, and the antibiotics treatment is still ongoing. This shows that such cases could be diagnosed based on histological findings and anaerobic culture using a fine-needle biopsy specimen, and unnecessary surgery may be avoided. In the case of tumors developed in the residual pancreas without typical malignant imaging findings, pancreatic actinomycosis should be considered as a differential diagnosis.

[A case of pancreatic actinomycosis diagnosed by EUS-FNA].

A 60-year-old male patient had alcoholic chronic pancreatitis. Three months prior, he had undergone an exchange of pancreatic duct stents. In December 201X-1, magnetic resonance imaging and computed tomography (CT) scan results showed a caput pancreatic mass and common bile duct dilatation. We considered that it was because of chronic pancreatitis and decided to follow up by imaging studies. Further, in March 201X, a CT scan result revealed worsening of the mass and bile duct dilation. We assessed the mass by endoscopic ultrasound and fine-needle aspiration. Histological findings revealed to an interstitial tissue infiltrated by several neutrophils and plasma cells and abscess-forming inflammation like sulfur granule. The mass was improved by antibiotic administration for 6 months.