Prostatic stromal tumor of uncertain malignant potential presenting as a huge bladder mass: an unusual case

left psoas major lesion was neurofibroma, which excluded metastatic STUMP. After one year of follow-up, there was no sign of metastasis or recurrence. Prostatic STUMP, arising from specialized hormone-dependent mesenchymal cells of the prostate, is a quite rare neoplasm. To our knowledge, prostatic STUMP presenting as a huge bladder mass has not been reported yet. Prostatic STUMP is manifested by mitotic figures, necrosis, and stromal over-growth, as distinguished from prostatic stromal sarcoma (PSS). 1 The ages of prostatic STUMP patients generally ranged from 25 to 83 years. The most common clinical symptoms are non-specific, including acute or chronic urinary obstruction, hematuria, hematospermia, dysuria, and rectal dysfunction. DRE may reveal perceptible nodule. The serum PSA level is usually at a normal level or elevated mildly, which could be distinguished from other prostatic adenocarcinoma. In our case, the patient, with normal PSA, was 53-year-old. The MRI of our patient indicated a large mixed solid cystic mass rooted in the transitional zone of the prostate, which protruded into bladder. The mass had homogeneous low-signal on T1-weighted imaging, but it was diffusely heterogeneous signal on T2-weighted imaging. The prostatic STUMP usually localized in the peripheral zone and/or transition zone, based on previous reports. 2 There was no reports about the prostatic STUMP with characteristics of arising from the transitional zone, protruding into the bladder and presenting as huge bladder mass. Besides, the MRI feature of prostatic STUMP is different from low signal of prostatic adenocarcinoma on T2-weighted imaging. 3 Since current radiology techniques are unable to differentiate STUMP from some other mesenchymal neoplasms, B-ultrasonography guided needle biopsy is usually necessary for diagnosis. Dear Editor, We describe a rare case of prostatic stromal tumor of uncertain malignant potential (STUMP) presenting as a huge bladder mass. Based on the previous literature, prostatic STUMP has a low incidence of morbidity. To the best of our knowledge, this is the first report of prostatic STUMP presenting as a huge bladder mass. A 53-year-old male patient did not have any antecedent injury, but complained of pain in his left back and lower urinary tract symptoms (LUTS) for 11 months. LUTS were manifested as nocturia, urinary frequency, and progressive urinary retention without hematuria. This patient also presented with fever and weight loss lasting for 1 month. His intermittent back pain was localized to the left lumbosacral region and usually triggered from hard labor. Digital rectal examination (DRE) revealed an enlarged …