[Metastasis to the sternum or parasternal recurrence of breast carcinoma? Value of sonography].

Because of the high tendency of breast cancer to develop metastatic deposits in the skeleton, space-occupying processes in the sternal region are mostly attributed to osseous metastases and not to parasternal lymph node involvement, even in case of solitary lesions, primary tumor localizations in the inner quadrants, positive axillary nodes and negative X-ray or bone scan findings. The sonographic examinations of 115 patients with breast cancer and clinical and/or scintigraphic suspicion of sternal metastasis, however, revealed the typical bone metastases of the sternum with a small soft tissue tumors in only 27.8 %, whereas 59.1 % of the cases showed parasternal recurrences; 5.2 % had both. Non-tumorous changes were seen in 6.1 %, equivocal results in 1.7 %. Solitary osseous metastasis of the sternum was rare; multiple skeletal lesions were found in the majority of this group in contrast to the patients in the parasternal relapse group, which moreover showed strong overrepresentation of the primary tumor localization in the inner quadrants. X-rays of the chest or the sternum were often false-negative and not reliable, the bone scans positive only in cases of secondary sternal invasion or skeletal metastases. Concerning reliability and cost, sonography was the imaging method of first choice for diagnosis, therapy planning and follow-up for space-occupying processes in the sternal region, with CT or MRI as adjuncts in cases of extended tumors invading the mediastinum.