Development of malignant lymphoma subsequent to breast cancer

The development of malignant lymphoma following breast cancer has not been described before. Here we report the development of malignant lymphoma at the ipsilateral chest wall subsequent to the surgical treatment of breast cancer. A 48-year-old woman underwent modified radical mastectomy due to breast carcinoma. Tamoxifen (10 mg twice daily) was given 3 years after the operation and continued for about 3 years. The patient was well until she recently (17 years after the initial operation) noted a small lump at her left anterior chest wall near the axilla. The local tumour mass was initially assumed to be a local recurrent lesion of breast cancer. Excisional biopsy was performed and eventually was histologically diagnosed to be malignant lymphoma. In view of the therapeutic implication, the development of second malignancy should not be mistaken as a progression of the known primary malignancy. Only with the awareness of such entity, can the prompt diagnosis and proper treatment be achieved.