Uncommon cause of an inflammatory pancreatic head tumor. Diagnosis: Purulent actinomycosis and incidental T1-carcinoid of the pancreatic head

Actinomycosis mimicking a pancreatic head neoplasm: A case report

Introduction

Actinomycosis is a chronic suppurative disease caused by a filamentous, Gram-positive, facultative anaerobic bacterium Actinomyces. Abdominal actinomycosis accounts for 10 to 20% of reported Actinomyces infections and pancreatic involvement is extremely rare.

Presentation of case

We report the case of a 64-year-old man who presented with a 3-week history of abdominal pain, nausea, weight loss, and icterus. Abdominal CT scan revealed a 3.5 cm heterogeneously enhanced mass of the pancreatic head, associated with mild dilation of the main bile duct and the Wirsung duct. The diagnosis of pancreatic head malignancy was highly suspected and surgical management was decided. Intraoperatively, a 3 cm indurated mass of the pancreatic head was found. Whipple's procedure was performed. Histopathological examination revealed pancreatic actinomycosis.

Discussion

Pancreatic actinomycosis is extremely rare. To our knowledge, only 18 cases have been reported in the English literature to date. It commonly presents as a slow-growing mass with bile and pancreatic ducts obstruction, which can mimic malignancy. Therefore, it has often been misdiagnosed and over-treated with futile surgery, when medical treatment based on antibiotherapy is the only required treatment.

Conclusion

We reported a rare observation of surgical management of actinomycosis mimicking a pancreatic head neoplasm. As clinical and radiological findings are nonspecific, the accurate diagnosis can only be made by histology. Through our case, we aim to highlight the importance of preoperative suspicion of pancreatic actinomycosis, given the still relevant morbidity of pancreatic resections.

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Actinomycosis is a chronic suppurative disease caused by a filamentous, Gram-positive bacterium Actinomyces

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Pancreatic actinomycosis is extremely rare

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It commonly presents as a slow-growing mass which can mimic malignancy

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Treatment is based on intravenous penicillin followed by oral penicillin for 6 to 12 months.

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Preoperative diagnosis of pancreatic actinomycosis is important, given the still relevant morbidity of pancreatic resections

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.

[Actinomycosis Involving Chronic Pancreatitis: A Case Report with Literature Review]

Actinomycosis is a slowly progressive, chronic infectious disease. It is caused by the genus Actinomyces, which are gram-positive anaerobic bacteria. It presents as a mass-like lesion, composed of bacterial nidus and characteristic granulomatous inflammatory fibrosis. As such, it has frequently been mistaken for a malignancy. Surgical resection is a common procedure in these patients prior to a definite diagnosis. Although actinomycosis can occur in a variety of regions, including oral-cervicofacial, thoracic, and abdominopelvic cavities, the involvement of the pancreas is very rare. We report a case of a 44-year-old male with a symptomatic actinomycosis caused by a mass in the tail of the pancreas. The diagnosis was made using an endoscopic ultrasound-guided fine needle aspiration biopsy without surgical resection. After the treatment with antibiotics, the pancreatic mass was confirmed to be resolved on the follow-up computed tomography.