Interstitial cystitis/bladder pain syndrome (IC/BPS) is a heterogeneous disease consisting of distinct subgroups of patients who have different underlying pathophysiology. Thus, the proposal by Prof. Petros that loose or damaged uterosacral ligaments (USLs) may be an important etiology outside the bladder to induce or worsen the symptoms of IC/BPS due to altered urothelial receptor sensitivity is interesting. However, for the proper diagnosis and treatment of IC/BPS, it is necessary to first identify bladder-centric pathophysiology including Hunner lesions by using cystoscopy and also prove that identified bladder mucosal abnormalities are the causes of bladder pain, for example, as shown by pain reduction following intravesical lidocaine instillation in the recent dimethyl sulfoxide clinical trial in IC/BPS patients [1,2]. Then, in the case that bladdercentric pathophysiology is less likely to be involved in IC/BPS symptoms, outside-bladder etiology such as the lax USL discussed here should be considered as a cause of bladder symptoms in IC/BPS patients. There will be no bright future for IC/ BPS without the following 3 steps: (1) understanding the symptoms, (2) detecting abnormal findings in or outside the bladder, and (3) verifying that the abnormality is the cause of the symptoms.