Follicular Cystitis, a Rare Diagnosis in an Emergency Setting: A case report and literature review

Introduction and importance: Follicular cystitis (FC) is a rare inflammatory disorder of the bladder that predominantly affects women. The exact cause of FC remains largely unknown, although it has been associated with inflammatory processes and bacterial infections, particularly following urinary tract infections. Regarding orphan diseases, like follicular cystitis, where large-scale trials seem virtually impossible, case reports find their place and guide the scientific community to find the best course of action. Case report: We present a case of an 87-year-old female patient who presented to the emergency department with gross hematuria that could not be managed by catheterization and continuous bladder irrigation and therefore required surgical management in the operating room with a transurethral resection of the bladder tumor and evacuating the blood clots. The histopathology study revealed the uncommon case of follicular cystitis. Clinical discussion: Being a rare inflammatory bladder condition, the pathophysiology is unknown, with inflammatory processes and bacterial infections commonly mentioned but not proven. We give an overview of this unusual condition, including its histological diagnosis, differentials, and potential treatment options. Conclusion: Several management strategies have been proposed to treat FC. Given the rarity of the condition, we do not expect to see recommendations based on large population studies, emphasizing the necessity of case reports in assisting urologists in practice.