Prostatic Stromal Tumor with Fatal Outcome in a Young Man: Histopathological and Immunohistochemical Case Presentation

Abstract

Stromal tumors of the prostate are rare and only a few cases have been described in the literature, including exceptional cases of stromal tumors with unknown malignant potential (STUMP) and a fatal outcome in young patients. Morphologically distinguishing a STUMP from a stromal sarcoma of the prostate (PSS) is still a challenge. We describe the histopathological and immunohistochemical findings in a 34-year-old man with a malignant specialized cell stromal tumor of the prostate that was diagnosed initially as STUMP, and he developed lung metastases within a few months. The patient attended our hospital because of lower urinary tract symptoms, after having excreted tissue through the urethra a few months before. Ultrasonography and urethrocystoscopy examinations showed a mass arising from the verumontanum, and a transurethral resection (TUR) revealed a highgrade spindle cell sarcoma reminiscent of a phyllode tumor of the breast. The tumor cells were immunoreactive for vimentin, progesterone receptor and, focally, CD34. The preliminary histological findings were subsequently confirmed after radical prostatectomy. The patient developed bilateral lung metastases and died 25 months after the initial diagnosis. Although rare in young patients, the challenging differential diagnosis of STUMP and PSS means that a prostate STUMP diagnosis made on the basis of biopsy or TUR specimens also requires urethrocystoscopic monitoring for the early detection of any progression to PSS. Radical prostatectomy should also be carefully considered.

MRI Appearance of Prostatic Stromal Sarcoma in a Young Adult

“…Leiomyosarcoma is the most common histological subtype of prostate sarcoma seen in adults (6). Prostate stromal sarcoma is rarer with fewer than 30 documented cases (1)(2)(3)(4)(5)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). Most patients with prostatic sarcoma, including PSS, present with symptoms of urethral obstruction (1-3, 5, 6), as in the present case.…”

“…The mass effect of the tumor, mainly located in the central gland, probably caused the early onset of symptoms (17). In previous reports on PSS, age at diagnosis has ranged from 19 to 86 years (mean, 48 years) (1)(2)(3)(4)(5)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). PSA levels in patients with PSS including the present case have been relatively low (0.1-4.5 ng/mL) in comparison with prostatic adenocarcinoma (1,(3)(4)(5).…”

Incidental Prostatic Stromal Tumor of Uncertain Malignant Potential (STUMP): Histopathological and Immunohistochemical Findings

“…In some cases STUMPs may represent a focal incidental lesion. Therapy varies from a wait-and-see approach to a radical retropubic prostatectomy (RRP) but their management and prognosis are still uncertain (4,5). We describe the case of a patient that referred to the Department of Urology, Sapienza Rome University, with acute urinary retention (AUR) and bladder overdistention.…”

Non‐epithelial neoplasms of the prostate

“…These tumours are derived from the prostatic specialized stroma, and include pure mesenchymal and mixed stromal and epithelial tumours (phyllodes) 4–28 . Stromal tumours are divided into stromal tumour of uncertain malignant potential (STUMP) and prostatic stromal sarcoma (PSS) 4,5 .…”

“…PSS is characterized by stromal overgrowth, increased cellularity, pleomorphism, the presence of increased mitosis, and necrosis (Figures 5 and 6). 4,5,[25][26][27][28] Biphasic phyllodes tumour exhibits similar sarcomatous stroma, but the epithelium is benignappearing ( Figure 7). [13][14][15][16][17][18] PSS is composed mainly of sarcomatous spindle cells, 4,5 in a storiform, fibrosarcomatous or patternless arrangement, but epithelioid and rhabdoid morphologies may also occur.…”