P2.213: Full As a Flask: A Case Report of Pediatric Prostatic Embryonal Rhabdomyosarcoma

Introduction: Prostatic Embryonal Rhabdomyosarcoma (ERMS) is a rare and aggressive malignant tumor that originates from undifferentiated premature mesenchymal cells in the prostate. It predominantly affects children, specifically male infants, making it the most common prostatic sarcoma in this age group, however most reported cases remain undiagnosed until adulthood. We present a rare case of a 20-month-old infant with a diagnosis of prostatic ERMS.

Case Description: A 20-month-old male with no medical history presented to the pediatric emergency department (ED) with a chief complaint of lethargy, abdominal pain, vomiting and reported blood in stool. At home, the patient was noted to be bearing down by caregivers and appeared uncomfortable along with pink-red stains and undigested food in the diaper. Associated symptoms included decreased activity, minimal oral intake and multiple episodes of non-projectile spit-ups. History positive for daycare attendance. Family history was non-contributory and initial vital signs within normal limits for age. Physical examination demonstrated a tired appearing child with congestion, rhinorrhea, mild suprapubic distention with tenderness on palpation. Initial laboratory results with thrombocytosis, mild transaminitis and mild elevation of erythrocyte sedimentation. A point-of-care ultrasound showed a distended bladder with pre-void volume measuring 175 cm3. Urine output of 170 cc with visibly dark appearance was noted after straight catheterization with improvement in clinical status. Urinalysis showed dark, turbid appearance and trace protein without blood. Patient had a non-stimulated penile erection and ongoing urinary retention was noted in the ED for which he received a sodium phosphate enema and urology was consulted. A magnetic resonance imaging of the abdomen revealed a 5.4 cm pelvic mass originating from the right aspect of the prostate, extending to the membranous and bulbar urethra of the base of the penis with suspicions of a rhabdomyosarcoma involving the prostate originating from the right aspect of the prostate and displacement of the urethra to the left with infiltration into the bladder and penile bases and anus (Image 1). A focused prostate ultrasound revealed an enlarged homogeneous, hyperemic, non necrotic prostate of 3 x 2.5 x 2.8 cm (Image 2). Pathology after a cystoscopy and transurethral biopsy revealed a prostatic ERMS. Chemotherapy was initiated after a bone marrow biopsy and a positron emission tomography scan.

Discussion: Acute urinary retention relieved by straight catheterization or enema is not always constipation. Most common neoplastic causes of pediatric acute urinary retention include prostatic ERMS and relapsing Burkitt’s lymphoma. Keeping a broad differential diagnosis is crucial in pediatric patients presenting with acute urinary retention and emphasis must be placed on a detailed physical exam and history. Behavioral voiding dysfunction should always be considered as a diagnosis of exclusion.

Conclusion: Prostatic ERMS, although rare, should always be considered in the differential diagnosis of pediatric patients with acute urinary retention.