ESR1 and Fibroadenoma: In 2006, Atwal published a case of previously documented supernumerary mammary tissue-originated vulvar fibroadenoma, describing a lesion that histopathologically mimicked a fibroadenoma with positive estrogenic receptors by immunohistochemistry and with healthy mammary tissue surrounding the lesion.[3] The presence of ectopic mammary tissue of normal characteristics surrounding a lesion described as fibroadenoma supports the theory of ectopic mammary tissue, and concludes that not all fibroadenomas derive from anogenital glands similar to breast, as Van der Putte confirmed.