Radiological Findings and Surgical Outcomes of Pulmonary Metastases Originating from Biliary Tract Carcinoma

Purpose: Metastasis to the lungs arising from biliary tract carcinoma (BTC) is extremely rare, and the patient characteristics and prognosis are not well known. We aimed to identify the imaging findings of pulmonary metastases originating from BTC and the eligible indications for surgical treatment.

Methods: Fifteen patients who underwent pulmonary resection for metastases originating from BTC were retrospectively analyzed.

Results: The primary sites included cholangiocarcinoma (n = 12) and gallbladder carcinoma (n = 3), and all cases were histologically diagnosed as well to moderately differentiated adenocarcinomas. The median disease-free interval between resection for the primary site and the detection of pulmonary metastasis was 30 months (range 0-144 months). Nine patients had a single lesion, and six had multiple lesions. As features of pulmonary lesions on thin-section computed tomography (CT), many appeared as solid nodules with smooth margins, whereas six lesions were concomitant with spiculation or pleural indentation, three with air bronchogram or ground-glass attenuation, and one with intra-tumoral cavity, and six cases with solitary pulmonary lesion were diagnosed as primary lung cancer before metastasectomy. The 3-year survival rate in the 11 patients who underwent complete metastasectomy was 45%. A disease-free interval of more than 3 years (p = 0.03) and single lesion (p < 0.01) were significant prognostic factors.

Conclusions: The CT findings of pulmonary metastases from BTCs sometimes resemble the characteristic findings of primary lung cancer. A long disease-free interval and single lesion are therefore considered to be good surgical indicators.