57 An unusual Presentation of Benign Prostatic Hyperplasia with Pure Stromal Hyperplasia as a Large Isolated Pelvic Mass with Normal Prostate Imaging

Introduction/Objective Benign prostatic hyperplasia (BPH) is the most common benign tumor in aging men. However, diagnosing BPH can be challenging when it presents as an exophytic pelvic lesion, particularly if imaging does not indicate anatomic continuity between the prostatic bed and the lesion. Methods/Case Report A retrospective study was performed to evaluate radiologic and pathologic findings of the lesion. Results Here, we report a case of a 57-year-old male presenting with a solitary solid pelvic mass, 11.9 cm in greatest dimension. Pathologic evaluation of the biopsy specimen showed a very hypocellular lesion consisting of bland spindle cell proliferation and small blood vessels within a loose fibrous stroma. Immunohistochemical staining demonstrated that the tumor cells were positive for CD34, desmin, androgen receptor (AR) and progesterone receptor (PR). The constellation of histomorphological and immunohistochemical profiles was consistent with BPH with pure stromal proliferation. Conclusion To our knowledge, this represents the first documented instance of BPH with pure stromal hyperplasia manifesting as a distinct pelvic mass without radiologic continuity with the prostate. This case highlights the need for clinicians and pathologists to consider BPH as a potential diagnosis in cases of large pelvic soft tissue lesions, especially in the setting in which standard prostate imaging appears normal and prostatic glands are absent.