This case-insensitive code system http://hl7.org/fhir/us/breast-radiology/CodeSystem/AbnormalityFibroadenomaTypeCS defines the following codes:

Code	Display	Definition
Fibroadenoma	Fibroadenoma	A fibroadenoma is a benign, or noncancerous, breast tumor. Unlike a breast cancer, which grows larger over time and can spread to other organs, a fibroadenoma remains in the breast tissue. Most are only 1 or 2 centimeters in size. [www.webmd.com > breast-cancer > what-are-fibroadenomas]
FibroadenomaDegeneration	Fibroadenoma degeneration	These are non-cancerous breast lumps. Fibroadenomas usually go away with age. By the time an individual is menopausal, Fibroadenomas degenerate.