—Cunningham21 stated that the growth of neoplasms of the bladder, either benign or malignant, although variable, may be quite rapid; he cited 2 highly malignant cases in which the neoplasms attained considerable size, one within nine weeks and the other within six months.In a consideration of whether misbehaved cells of the bladder which produce benign tumors may subsequently become malignantly active, Bumpus stated that this change was never observed at the Mayo Clinic, and both Cunningham and Bumpus believe that tumors of the bladder are either benign or malignant from their inception. The disagreement on this subject is substantiated by much evidence. Ewing stated that recurrence of benign tumor usually represents development of new growths from preexisting lesions and such recurrence is not an implantation of the old growth. Recurrent malignant tumors are more likely to be the result of retained cell groups in the submucosa.
SCHOLL AJ, JUDD ES, KEYSER LD, VERBRUGGE J, KUTZMANN AA, HEPLER AB. A REVIEW OF UROLOGIC SURGERY. Arch Surg. 1932;24(4):687-714. doi:10.1001/archsurg.1932.01160160159011