Microfibrillar collagen hemostat (Avitene™) can mimic peritoneal metastases after primary percutaneous bile duct...

Primary Percutaneous Stenting (PPS) is a novel drainage technique for malignant hilar biliary obstruction (MHBO), typically caused by perihilar cholangiocarcinoma. During PPS, the percutaneous tract is sealed with Avitene™ Microfibrillar Collagen Hemostat (MCH) to avoid an external drain. This report describes the radiological, intraoperative, and histopathological appearance of MCH following PPS in resectable MHBO.

We reviewed all patients with MHBO who underwent PPS and surgical exploration at two Dutch academic hospitals between 2022-2025. Macroscopic findings were documented by the surgeon, and tissue from suspicious lesions was evaluated with frozen section and definitive histology to differentiate malignant lesions from reactive ones due to MCH deposits.

Twenty-one patients underwent surgical exploration after PPS. In fourteen patients, white-yellow capsular lesions were identified at the PPS puncture site that were macroscopically suspicious for peritoneal metastases. Histology revealed foreign body reactions with eosinophils, giant cells, amorphous material, and focal necrosis. No malignant cells were identified. Two patients had peritoneal metastases, yet the lesions along the PPS tract were negative for malignancy.

MCH deposits along the PPS puncture tract can resemble PM during surgical exploration. Recognizing this characteristic appearance is important to prevent misinterpretation and alter surgical decision making.