Bone formation associated with osseous metastases from bladder carcinoma

Twenty-four cases of carcinoma of the urinary bladder, involving bone, have been reviewed. Eighteen of these were distant metastases beyond the pelvis. The lesions were predominantly osteolytic. Ossification in the soft tissues adjacent to the bone metastasis was observed in three cases, all involving the left tibia. The reason for this site of predilection remains obscure.