Nodular mucinosis of the breast in a supernumerary nipple: case report and review of the literature.

Nodular mucinosis is an extraordinary stromal lesion of the breast. The usual clinical presentation is that of an oozing, slow-growing, soft, non-tender, lobulated mass in the subareolar region. Histologically, it is a non-encapsulated myxoid/mucinous lesion with a sparse infiltrate of spindle cells within a collagenized stroma. The histogenesis of nodular mucinosis is undetermined but the pattern of staining of the spindle cells suggests it might be of myofibroblastic origin. We herein report for the first time in the English literature a case of nodular mucinosis occurring in a supernumerary nipple. We also discuss the main differential diagnoses and review the literature of previously published cases of this entity.