[A malignant tumour in the breast is not always primary breast cancer].

In a 75-year-old woman with a swelling in her left breast, a 39-year-old woman with an anal fissure due to diarrhoea and a 65-year-old woman with chest pain, a mammary tumour was diagnosed that did not originate in mammary tissue. These were a recurrent melanoma, a carcinoma of the thyroid and a B-cell lymphoma, respectively. All patients were treated. The first patient developed new metastases one year later, the second died, partly as a result of the tumour, and the third showed no recurrence of the tumour after two years. Breast cancer is one of the most frequently occurring neoplasms in women. Primary tumours in the breast from other origins and metastatic lesions to the breast from extramammary tumours are rare. Most of these cases concern haematological malignancies and metastases from melanoma and lung cancer. Despite the fact that metastases to the breast are rare, one should always consider the possibility.