Mucinous breast cancer with solitary metastasis to humeral head: a case report.

Breast cancer is the most common cause of metastatic deposits in the skeleton, and bone is the most common site of recurrence of breast cancer. Breast cancer metastasis most commonly affects the spine, ribs, pelvis, and proximal long bones; however, only 3.5% of breast cancer patients develop long-bone metastases. The humerus is the most common upper-extremity site for bony metastasis, and pathologic fractures can result. The patient in the current study presented with breast cancer and discovered to have humeral head metastasis during initial workup. The dilemma was in investigation the modality to confirm humeral head metastasis as there are many differential diagnoses with similar findings. After staging workup, the patient was treated with neoadjuvant chemotherapy followed by modified radical mastectomy and radiotherapy of the chest wall and the shoulder. The lesion in humerus was well healed.