P-HPB-03: Role of endoscopic ultrasound in the evaluation of patients with metastases of suspected pancreaticobiliary origin: A pilot study

BACKGROUND AND OBJECTIVES: Carcinoma of unknown primary (CUP) origin accounts for 3%–5% of cancer cases. Endoscopic ultrasound (EUS) is an excellent modality to evaluate the pancreaticobiliary tract. However, its role in evaluation of patients with CUPs has never been studied. This pilot study is a retrospective study of prospectively collected data to evaluate whether EUS is effective in diagnosing hitherto unidentified pancreaticobiliary primary in patients with CUPs. PATIENTS AND METHODS: Ten patients with CUPs with suspected pancreaticobiliary origin were referred to us for the evaluation of pancreaticobiliary tract using EUS. All the patients had normal pancreas and biliary system on previous imaging including positron emission tomography/computed tomography. Patients underwent EUS using a linear echoendoscope. RESULTS: Two of the ten patients (20%) were found to have lesions on EUS, both in the gallbladder and in the neck region. The lesions measured 6 and 8 mm in diameter. Both the lesions were sampled successfully, and adenocarcinoma was detected. None of the lesions had mucinous morphology. There were no periprocedural complications. CONCLUSION: EUS is an effective modality to detect occult primary in patients with CUPS with suspected pancreaticobiliary origin. Larger studies assessing its cost-effectiveness and identifying positive predictive factors are needed before incorporating EUS in the routine diagnostic workup of these patients.