Isolated insulin-derived amyloidoma of the breast.

Isolated amyloidomas derived from insulin are extremely rare, and there is only one reported case to date of insulin-derived amyloidoma in the breast.We present the case of a 36-year-old woman reporting a lump in the right breast. It was clinically assessed as a probable fibroadenoma but was removed surgically given the size of the lesion. On histological analysis, the lesion had features consistent with amyloid. Further investigations showed the amyloid to be derived from insulin. The lump was removed in its entirety, and the patient made a full recovery.