Giant sarcoma of the prostate stroma: Clinical, radiological and histopathological analysis of a rare prostatic cancer

Abstract

Prostate sarcoma is extremely rare, comprising less than 0.1 % of prostate cancers.

A 61-year-old male presented to the emergency department with urinary retention and hematuria. Upon resolution of urinary retention, abdominal computed tomography showed a giant prostatic tumor, of approximately 1700 cubic centimeters, causing bilateral ureteric obstruction, and invasion of rectum and sigmoid colon. Laparotomy due to bowel obstruction showed peritoneal carcinomatosis. Palliative chemotherapy was initiated; however, he died due to hematological toxicity related to doxorubicin.

Radical surgery is the ideal treatment; in cases of advanced or metastatic disease, adjuvant or palliative chemotherapy or radiotherapy withholds little or no benefit.

1. Introduction

Prostate cancer is one of the most frequent cancers worldwide, however, prostate sarcomas are extremely rare, comprising less than 0.1 % of all cases of prostate cancer. Specifically, prostate stromal sarcomas represent only 7 % of all prostate sarcomas.¹ Little is known about the etiology or physiopathology of prostate sarcomas; however, some studies have tried to identify specific characteristics related to prognosis in these patients. Several studies have found that metastatic disease at diagnosis, failure to perform radical surgery, and positive surgical margins are some factors related to poor prognosis.^1,2 Management with adjuvant or palliative radiotherapy or chemotherapy seems to add little or no benefit to the survival outcomes in these patients.¹ We present a rare case of a giant sarcoma of prostate stroma.

2. Case presentation

A 61-year-old male presented to the emergency department due to acute urinary retention after repeated episodes of intermittent gross hematuria. The patient had no previous comorbidities; however, he underwent transurethral surgery of the prostate at a private practice two months before arriving to our emergency department, due to a previous episode of urinary retention, nevertheless he did not receive any histopathological results or specific diagnosis after the surgery. Upon our urological evaluation, the patient had acute pain of maximum intensity related to urinary retention, on physical examination the patient had tachycardia, hypotension, diaphoresis, and abdominal bloating due to palpable bladder, digital rectal examination proved a fixed, indurate prostate, multiple unsuccessful attempts of transurethral Foley catheter insertion were done, therefore, urgent bedside ultrasound-guided percutaneous cystostomy was performed. During bedside suprapubic ultrasound, a massively distended bladder with several intravesical blood clots was found, complete visualization of the bladder and the prostate was not possible, however, cystostomy was successfully placed, obtaining frank hematuria. Blood tests showed several abnormalities, severe anemia (hemoglobin 8.8 g/dL; hematocrit 29 %), hyponatremia (125 mmol/L), leukocytosis (17 × 10ˆ3), elevated serum creatinine (1.7 mg/dL), neutrophil count (88 %) and C reactive protein (21 mg/dL). After nephrological consultation, a contrast enhanced computed tomography was performed, observing a giant prostatic tumor projecting inside the bladder (20 × 12 × 13 cm, with a volume of approximately 1700 cubic centimeters), causing bilateral partial obstruction of the ureters, with invasion of the rectum and sigmoid colon (Fig. 1). Serum prostate specific antigen showed a value of 0.56 ng/mL. The patient was immediately managed with blood transfusion. Antibiotic treatment with Ertapenem was also initiated due to clinical and biochemical evidence of infection.

Fig. 1.

Abdominal computed tomography showing a high-volume prostate-dependent tumor (20 × 12 × 13 cm), occupying more than 50 % of the bladder lumen. A. Coronal view of the prostatic tumor. B. Sagittal view of the prostatic tumor, showing its largest diameter (20cm) and complete compression of rectum, with no evidence of a clear interface between them (arrowhead).

Following the previously described tomographic findings, the patient was managed with bilateral ultrasound-guided nephrostomies (7.5 Fr) and a transurethral resection of prostate was attempted. During endoscopic evaluation of the urethra and prostate, a whitish, solid prostate-dependent tumor was found, with macroscopic invasion of the urethra (Fig. 2). It was impossible to reach the bladder lumen through the rock-solid prostate tumor, despite wide bipolar resection, however several prostate tissue samples were taken for analysis, including segments of urethral invasion.

Fig. 2.

Cystoscopy showing the pale, whitish, poor vascularized appearance of the tumor, not compatible with the macroscopic appearance of common prostatic or urothelial tumors. A. Membranous urethra invaded by the tumor. B. Prostatic urethra with the prostatic tumor.

During the immediate postoperative follow-up, the patient remained stable hemodynamically, with significant improvement of abdominal pain and general discomfort, with adequate clear urine output through nephrostomies. Thirty-six hours after the placement of nephrostomies, the patient showed improvement of serum creatinine (0.9mg/dL). On the sixth postoperative day, the patient had severe bowel obstruction, and open laparotomy was performed, finding abundant carcinomatosis, with a fixed tumor invading the rectum and sigmoid colon, therefore a colostomy was performed. The patient showed adequate postoperative outcome following open laparotomy and colostomy.

Histopathological results from transurethral resection of prostate concluded a sarcoma of the prostatic stroma with abundant tumoral necrosis (Fig. 3). Consultation to oncology department was requested, and hospital discharge, due to complete infection and anemia response, was indicated on the 16th day after hospital admission. The patient started palliative chemotherapy with Doxorubicin on the 20th day following diagnosis. However, 12 days after Doxorubicin, the patient suffered febrile neutropenia due to chemotherapy toxicity. The patient died 1 month after urological diagnosis, from complications related to chemotherapy.

Fig. 3.

Histological appearance of the tumor, compatible of sarcoma of the prostate stroma. A. Hematoxylin Eosin (HE) stain at 10X augmentation, sarcomatous neoplasm, with fusiform cells and abundant necrosis. B. HE stain at 40X augmentation, enlarged cells with severe pleomorphism and hyperchromatism. C. Vimentin-positive stain, showing marked cellular pleomorphism, compatible with sarcoma. D. Vimentin-positive stain, showing abundant necrosis and thrombosis.

3. Discussion

Few large-scale studies have analyzed the incidence of urinary sarcomas, and even among those studies, few cases of prostate sarcomas have been found. Dotan Zohar and colleagues published a 25-year experience of genitourinary (GU) sarcomas of the Memorial Sloan-Kettering in 2006. Of the reported 131 cases of genitourinary sarcomas, only 21 cases of prostate sarcomas were found, 9 were rhabdomyosarcomas and 8 were leiomyosarcomas, however, no specific detail on the remaining 4 patients' histology is reported, nor any specific evidence related to the patients' outcome.³ Nazemi Azadeh and colleagues published the largest casuistry of genitourinary sarcomas so far, in 2020, reporting 3007 patients with GU sarcomas from the United States SEER (Surveillance, Epidemiology and End Results) database, with a total of 234 prostate sarcomas, comprising 7.8 % of all GU sarcomas. No additional information regarding prostate sarcoma histology or outcomes is available.⁴ The most recent study about GU sarcomas was published in 2024 by Satoshi Nitta and colleagues, in Japan. They reported 155 sarcomas (comprising 0.1 % of al GU cancers from 121 different hospitals), out of which only 12 (7.7 %) were of the prostate gland. Even though no specific details about the patients’ outcome is reported, they concluded that prostate sarcomas have the worst prognostic amongst all GU sarcomas.⁵

Some studies have reported several risk factors and characteristics related to poor outcomes in patients with prostate sarcoma. Ding Beichen and colleagues analyzed 41 cases of prostate sarcoma. They reported a median age of 43 years, most cases were either leyomiosarcoma (24.4 %) or rhabdomyosarcoma (26.8 %), only 3 (7.3 %) cases of prostatic stromal sarcoma were found. Regarding patients’ outcomes, they found that the absence of metastasis and the possibility to perform a radical resection with negative margins were the only predictors of better overall survival.¹ John E Musser and colleagues reported 38 cases of prostate sarcomas over a 20-year period, with a median age of 50 years, and mostly leyomiosarcomas (34 %) or rhabdomyosarcomas (32 %), without reporting any prostatic stromal sarcoma. They also found that metastatic disease and tumor size are some factors related to poor prognosis.²

The preferred treatment of prostate sarcomas is not standardized, the most frequently reported treatment is radical surgery, either radical prostatectomy or pelvic exenteration, however, only the presence of negative surgical margins after radical surgery has been associated with improved survival.^1,2 Adjuvant chemotherapy has been described, however no real benefit on overall survival (OS) is achieved if positive surgical margins are found after surgery. As for adjuvant radiotherapy, it adds little or no benefit to overall survival.^1,2 In cases of metastatic disease, palliative chemotherapy is controversial, Ding Beichen and colleagues described similar overall survival in metastatic patients managed with palliative chemotherapy compared to prostatectomy followed by adjuvant chemotherapy (7.0 vs 5.0 months).¹ John E Musser and colleagues did not compare OS of metastatic patients managed with either palliative chemotherapy or surgical treatment with adjuvant chemotherapy, however, the OS of metastatic patients managed with surgery followed by chemotherapy was identical to the OS of the whole population of metastatic patients regardless of treatment (1.7 years vs 1.5 years).² Different chemotherapy agents and regimens have been described, with no apparent differences between them, cisplatin/doxorubicin, cisplatin/gemcitabine, gemcitabine/docetaxel, ifosfamide/mesna, and CyVADIC (vincristine, cyclophosphamide, adriamycin, dacarbazine), among others.¹

Our patient had several poor prognostic factors since diagnosis, apart from presenting severe anemia, acute kidney injury and sepsis, he had high volume disease, radiological evidence of locoregional advanced disease, and posterior evidence of peritoneal carcinomatosis. Palliative chemotherapy with initial doxorubicin was attempted, since there was no possibility of initial radical surgical treatment, yet the patient died one month after diagnosis. As has been previously described in the literature, our patient experienced a very limited overall survival, with no real response to palliative chemotherapy.

4. Conclusion

This case represents an extremely infrequent pathology, even among prostatic sarcomas, prostatic stromal sarcomas are extremely rare. Our patient had several characteristics that foretold a poor prognosis since the beginning, he had a huge tumor (20 cm of maximum diameter), radiological evidence of locoregional invasion at diagnosis, and posterior confirmation of metastatic disease (peritoneal carcinomatosis). It is impossible to assume what could have been the survival of our patient if he had not suffered from hematological toxicity related to chemotherapy, however, the poor outcome of our patient clearly matches the poor prognosis and short survival rates that have been previously reported by published papers in this type of cancer.

CRediT authorship contribution statement

Alan de Jesus Martinez Salas: Writing – review & editing, Writing – original draft, Visualization, Validation, Supervision, Software, Resources, Project administration, Methodology, Investigation, Formal analysis, Data curation, Conceptualization. Alfredo Valero-Gomez: Writing – review & editing, Resources, Project administration, Methodology, Investigation, Formal analysis, Data curation. Aldo Daniel Jimenez Garcia: Writing – review & editing, Project administration, Methodology, Investigation, Formal analysis, Data curation. Iñigo Navarro-Ruesga: Writing – review & editing, Project administration, Methodology, Investigation, Funding acquisition, Formal analysis, Data curation. Daniel Calvo-Mena: Writing – review & editing, Project administration, Investigation, Formal analysis, Data curation. Stefan Zilli-Hernandez: Writing – review & editing, Project administration, Methodology, Investigation, Formal analysis, Data curation, Conceptualization.