Imaging features of bone metastases from cholangiocarcinoma.

Purpose: Cholangiocarcinoma (CCA) is the second most common primary malignant hepatic tumor originating from bile duct epithelia. Bone metastasis is uncommon and less documented. The aim of this study was to characterize the imaging features of bone metastasis from CCA.

Methods: A retrospective descriptive imaging characteristics in 199 patients (1465 lesions) diagnosed as CCA with bone metastasis were evaluated based on plain radiography, computed tomography (CT), magnetic resonance imaging (MRI) and Tc-99 m methylene diphosphonate bone scan.

Results: The common vertebral metastatic sites were lumbar spines (94 [47.2 %], 95 %CI 40.1-54.4), upper thoracic spines (89 patients [44.7 %], 95 % CI 37.7-51.9), and lower thoracic spines (80 [40.2 %], 95 % CI 33.3-47.4). On plain radiograph, most of lesions had osteolytic pattern (68 %) with pedicular destruction (45.3 %) whereas on CT had mixed osteolytic and osteosclerotic destruction (40.8 %). The common non-vertebral metastatic sites were ribs and pelvis (80 patients [40.2 %], 95 % CI 33.3-47.4 and 60 [30.2 %], 95 % CI 23.9-37). On plain radiograph, in the long bones, usually had permeative destruction (58.9 %), whereas on CT showed mixed osteolytic and osteosclerotic (34.6 %). On bone scan, increased-uptake was the common pattern, found in the vertebral and non-vertebral sites (93.6 % and 92.4 %).

Conclusions: Bone metastasis from CCA usually occurred in the axial skeleton. The common patterns of destruction were osteolytic or mixed osteolytic and osteosclerotic. Periosteal reaction was scant in the appendicular long bones. On bone scan commonly had increased-uptake.