Locally recurring primary myxoma of the breast: an evidence of malignant alteration.

Breast is an extremely rare localization of myxoma. To date, only five cases have been reported, including one case of nerve sheath myxoma. In this report, the authors present a 37-year-old female patient who was admitted to the University Hospital for Tumors in Zagreb, Croatia, in 1979, with a 2-month history of gradually enlarging, painless subcutaneous mass in her right breast. On physical examination, a firm, relatively well circumscribed mass measuring 3 x 2 cm was detected in the upper outer quadrant and partly beneath the areola. The mass was freely movable to the overlying skin, causing no retraction. There was no family history of a breast disease or cancer. Patient's past history revealed no major illnesses or trauma. The tumor was removed by simple local excision, but it recurred locally in three episodes between 1981 and 1986. After that, the tumor underwent malignant alteration to myxosarcoma on its fourth (in 1992), and to myxoid liposarcoma on its fifth recurrence (in 1993). No such sequence of events has been reported in the literature so far.