"Uncommon Cause of Obstructive Jaundice: Actinomycosis Mimicking Malignant Disease"

Abdominal actinomycosis is a rare granulomatous infection caused by Actinomyces bacteria, typically presenting as fistulas, abscesses, or masses. Delayed diagnosis may hinder timely treatment, making early detection crucial.

A 60-year-old male with no significant medical history presented with obstructive jaundice due to a hilar mass involving the right bile ducts and the origin of the left bile duct (Klatskin type III A). Suspecting malignancy, a percutaneous biopsy was performed, yielding negative results. Endoscopic ultrasound (EUS) was attempted but failed due to insufficient access to the duodenal bulb. An exploratory laparoscopy revealed an inflammatory mass, which hindered proper sample collection.

In a second EUS, the duodenal bulb was accessible, and a poorly defined mass was identified in the hepatic hilum, involving the porta hepatis and adjacent to the hepatic artery. Elastography showed a blue pattern suggestive of malignancy. After two needle passes using a 22G biopsy needle and the "slow pull" technique, histopathological analysis revealed branching basophilic structures (PAS and silver stain positive), consistent with Actinomyces and no malignancy. Targeted antibiotic therapy was initiated, leading to a reduction in mass size and clinical improvement.

Biliary actinomycosis, often mistaken for malignancy due to its rarity, should be included in the differential diagnosis of abdominal masses. A comprehensive diagnostic approach, including EUS, is vital for effective identification and treatment.

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Artikel online veröffentlicht:
27. März 2025