Embryonal rhabdomyosarcoma of prostate combined with prostatic abscess in an adult patient: a case report and literature review

Abstract

Background: Embryonal rhabdomyosarcoma (ERMS) of the prostate is a rare and aggressive malignant tumor in adults with a poor prognosis in general. The main presenting symptoms are dysuria and acute urinary retention. Prostate ERMS is easily misdiagnosed, which leads to delays in treatment.

Case description: We report the case of a previously healthy 31-year-old man who presented with dysuria for 3 months. Digital rectal examination (DRE), ultrasound, and computed tomography (CT) were suggestive of the possibility of a 2.0 cm × 3.0 cm abscess in the left lobe of the prostate. Prostate-specific antigen (PSA) was at a normal level, and C-reactive protein (CRP) concentration was elevated. The patient underwent surgical drainage by transurethral incision of the prostatic abscess. There was a significant improvement in the maximal urinary flow rate on postoperative day 5. However, the patient presented with acute urinary retention again on the 20th postoperative day. DRE and pelvic magnetic resonance imaging (MRI) showed a recurrence of an enlarged mass in the left lobe of the prostate. PSA level was again normal. Cystoscopy revealed a large neoplasm arising from the prostate obstructing the bladder outlet, and a diagnostic transurethral resection of this prostate tumor was performed. Histopathology revealed the mass to be an embryonic rhabdomyosarcoma. Subsequently, the patient was transferred to the Oncology Department and received chemoradiotherapy. After chemoradiotherapy, the size of the prostate became normal. Unfortunately, the patient deteriorated rapidly and eventually succumbed to multiple organ failure 1 year after the initial presentation.

Conclusions: Due to its non-specific presenting symptoms, prostate ERMS can be easily misdiagnosed, which can lead to treatment delay. Multimodality approaches, including neoadjuvant/adjuvant chemotherapy, radiotherapy, and radical resection, can improve the survival rate and reduce ERMS patient mortality.

Keywords: Case report; chemoradiotherapy; embryonal rhabdomyosarcoma (ERMS); prostatic abscess.

Figure 1

Pelvic CT and MRI examinations. Arrows indicate the prostatic abscess. (A) CT imaging indicated a 2.0 cm × 3.0 cm abscess in the left lobe of the prostate, and the size of the prostate was 4.5 cm × 5.0 cm × 5.7 cm. (B) A follow-up pelvic MRI showed the prostatic abscess disappeared and interval improvement in the prostate after drainage of the prostatic abscess. The size of the prostate was about 3.5 cm × 4.0 cm × 4.5 cm. CT, computed tomography; MRI, magnetic resonance imaging.

Figure 2

Pelvic MRI and cystoscopy examinations. Arrows indicate the large mass. (A) Pelvic MRI revealed a large mass developed again in the left lobe of the prostate after surgery in 20 days. The size of the prostate was 4.5 cm × 5.6 cm × 7.2 cm. (B) Cystoscopy showed a large neoplasm arising from the prostate that obstructed the bladder outlet. MRI, magnetic resonance imaging.

Figure 3

The histopathology of the tumor. (A) Patternless sheets of primitive round to spindled cells show alternating hyper- and hypocellular zones with focal myxoid stromal matrix (H&E stain, ×200). (B,C) Some tumor cells show rhabdomyoblastic differentiation with dense eosinophilic cytoplasm (H&E stain, ×200, ×400). (D) Tumor cells with positive nuclear staining for myogenin (immunohistochemical stain, ×200). H&E, hematoxylin-eosin.