The diagnosis of breast pathology is made on imaging, cytology/histology and clinical exam. All three have to be clearly benign before you can pass off the "palpable mass". Unless you identify a definite benign etiology, the "palpable mass" deserves being sampled.
In general terms, if something worries you on imaging grounds, short term follow up rarely serves a purpose. If it worries you now it's going to still worry you in 6 months.
In every day breast practice the patient who finds an abnormality that turns out to be significant is quite common. Which makes it such a pity that it has become fashion to blow off breast self exam as not statistically helpful. The contrary is true in the trenches of everyday imaging life. The value of breast self exam is shown by cases like this with regular frequency.