Diffuse bone metastasis from cholangiocarcinoma involving the sternum: A case report and review of literature.

Cholangiocarcinoma (CCA) is a rare cancer of the bile duct epithelial cells and it commonly spreads to the regional lymph nodes, liver, and lungs. Bone metastasis has been reported in patients with CCA, involving both the axial and appendicular skeleton. Herein, we report a case of extrahepatic CCA with extensive bone metastases involving the calvarium, sternum, bilateral ribs and scapulae, entire spine, pelvis, and bilateral femur. To our knowledge, this is the first case report on sternum metastasis in CCA. The case presentation and review of literature highlighted the rarity of this metastasis, and health-care providers should be aware of the rare presentation of CCA.