Bilateral breast keloids in an elderly woman associated with bilateral breast cancers and high concentration of serum tumor growth factor-β.

We report a case of bilateral annular breast keloids in a 72-year-old woman who had been suffering from bilateral breast cancers. Histopathologically, the keloids showed unique distribution of α-SMA+, CD34- myofibroblasts and α-SMA-, CD34+ fibroblasts depending on the region. High serum levels of tumor growth factor-β were detected at 6 months after the development of the breast keloids, but not at 10 months. CD163-positive cells were abundantly detected in the skin of the elevated portion of the keloids. In contrast, these cells were considerably less numerous in the skin of the central healing portion compared with the skin of the elevated expanding portion. One interesting idea based on these results is that high levels of tumor growth factor-β released from CD163-positive cells played a crucial role in the formation of breast keloids through active induction of fibroblast differentiation into myofibroblasts. The present case strongly supports the previously proposed idea that keloids can form as a paraneoplastic phenomenon in breast cancer patients with keloid constitution.