Ciclosporin-induced accessory breast tissue: Dramatic improvement after dose adjustment

Accessory breast tissue is a relatively common congenital condition in which abnormal accessory breast tissue is seen as a mass anywhere along the course of embryologic mammary streak in addition to the presence of normal breast tissue. Ciclosporin therapy has been associated with benign breast disease in women. However, to the best of our knowledge, there are no reported cases of accessory breast tissue growth associated with ciclosporin therapy and regression after adjusting the dose. A 48-year-old woman had renal transplantation in 2009 with her brother as the donor. Her transplant follow-up over eight years had been unremarkable. She presented to our transplant follow-up clinic with bilateral painful axillary masses approximately 3 cm × 3 cm in diameter, not attached to the skin or underlying structures with no skin changes and no lymphadenopathy. Breast examination did not reveal any abnormalities. Her ciclosporin levels over the previous three years ranged between 130 and 150 ng/mL. These levels were within the acceptable recommended level of 100-150 ng/mL at that time (currently reduced to 80-120 ng/ml). Ultrasound of both axilla showed well-defined hypoechoic smooth outline masses in both axillary regions 3 cm × 4 cm. Fine-needle aspiration showed lesions consisting of cohesive ductal cells. The findings were consistent with accessory breast tissue with no evidence of inflammatory infiltrate or malignant changes. Her ciclosporin dose was reduced with the subsequent follow-up visits levels ranging between 90 and 110 ng/mL. Clinical examination four months later showed dramatic reduction in the axillary masses on both sides. Ultrasound confirmed the regression in the size of both masses. We conclude that ciclosporin was probably responsible for the formation of accessory breast tissue and reduction in the dose of ciclosporin resulted in substantial reduction in the tissue size.