A mammogram and rib and spine films were ordered by the physician. The mammogram shows a large mass consistent with cancer in her right breast and the bone films show multiple osseous lesions consistent with metastatic disease. Breast tissue may be found anywhere along the mammary or milk line from axilla to groin, but usually in the pectoral region between the clavicle , sternum , costal margin and axilla. Both breast and bone films would be ordered since one film will not show both simultaneously due to the differences in density. Since cancer is suspected with the lump in the breast, the film of the bones might show if there are any metastases to them.
Breast cancer can metastasize via the blood or via the lymphatic system.
The most likely route for the cancer to reach the bones would be through the intercostal veins, i.e. hematogenous spread. In addition to the bones one would suspect that the axillary lymph nodes , especially the pectoral group might be involved. If the cancerous cells had spread directly via the venous system the next organs in jeopardy would be the lungs, since they are downstream, so to speak, and would be the first capillary bed the cells came to after entering the vascular system. If the tumor cells overwhelmed the axillary lymph nodes , they too ultimately drain into the venous system where lymph enters the venous system at the junction of the internal jugular and subclavian veins. The prognosis would depend upon the extent of the metastases and which organs were involved.