Figure 1
Micturating cystourethrogram
Micturating cystourethrogram showing a lobulated filling defect in the posterior urethra. The bladder base is elevated.
Genitourinary rhabdomyosarcoma
SectionPaediatric radiology
Case TypeClinical Cases
AuthorsJ. Turkington, A. Paterson.
Connected authors
6 months, male
Clinical History
Increasing difficulty with micturition.
Imaging Findings
The patient presented with increasing difficulty with micturition. A micturating cystogram was performed (Fig. 1). Cystoscopy and biopsy showed this to be a rhabdomyosarcoma.
Discussion
Rhabdomyosarcoma is a highly malignant tumour that can occur at various sites throughout the body. It is the most common soft tissue sarcoma of the pelvis in children. The genitourinary tract accounts for 15-30% of rhabdomyosarcomas in children, with an annual incidence of 0.5-0.7 cases per million. The are two peak age ranges of incidence of genitourinary rhabdomyosarcoma: 2-6 and 15-19 years old. This second peak in adolescence is mainly due to paratesticular rhabdomyosarcomas.
There are three major histological types: embryonal, alveolar and pleomorphic. Embryonal is the most common type occurring in 50-60% of cases. A polypoid form of embryonal rhabdomyosarcoma known as sarcoma botryoides may be seen protruding into a hollow viscous, such as the bladder, appearing like a "bunch of grapes". Genitourinary rhabdomyosarcoma can occur in the bladder, prostate, paratesticular tissues, vagina and uterus. Sites of secondary spread include lymphatic, lung, bone and liver metastases, being present in approximately 20% of cases at the time of diagnosis.
Bladder rhabdomyosarcoma occurring in the trigone often presents with bladder outlet obstruction. Gross haematuria and signs of urinary tract infection may also occur. The botryoides form can enlarge into a palpable suprapubic mass.
Prostatic rhabdomyosarcoma tends to present as a solid mass, and local extension into the bladder and posterior urethra results in bladder outlet obstruction. Infiltration of the rectal wall can lead to constipation. Paratesticular involvement causes painless scrotal swelling. Vaginal rhabdomyosarcoma is usually of the botryoides type. It presents with vaginal discharge, bleeding or vaginal extrusion of the tumour or urethral obstruction secondary to local invasion. Uterine rhabdomyosarcomas may arise de novo or due to secondary extension from the vagina.
Radiological investigation would initially include ultrasound for a child presenting with a palpable abdominal mass. A lobulated soft tissue mass of homogeneous echo-texture similar to that of muscle, within or displacing the bladder, suggests a diagnosis of pelvic rhabdomyosarcoma (Fig. 2). A MCUG may show a filling defect in the bladder, or elevation of the bladder base in prostatic rhabdomyosarcomas, or distortion and elongation of the posterior urethra. CT (Fig. 3) and pelvic MRI are used to evaluate for local invasion and to detect distant metastatic disease.
Treatment includes initial chemotherapy followed by restaging using CT, cystoscopy and biopsy. A good response would be followed up with radiotherapy, a poor response with extirpative surgery. The patient in this case had no evidence of metastatic disease at presentation. Following chemotherapy and radiotherapy he remained well for 18 months, after which time he developed extensive local tumour recurrence. He died at the age of 2 years and 6 months from bronchopneumonia; he was immunocompromised following chemotherapy.
Differential Diagnosis List
Genitourinary rhabdomyosarcoma
Final Diagnosis
Genitourinary rhabdomyosarcoma
References
[1] Shapiro E, Strother D. Pediatric genitourinary rhabdomyosarcoma. J.Urol.1992 Dec,148:1761-8. (PMID: 1433603)
[2] Loughlin KR, Retik AB, Weinstein HJ, Colodny AH, Shamberger RC, Delorey M, Tarbell N, Cassady JR, Hendren WH. Genitourinary rhabdomyosarcoma in children. Cancer. 1989 Apr,63:1600-6. (PMID: 2924267)
[3] LaQuaglia MD. Genitourinary rhabdomyosarcoma in children. Urol Clin. N. America. 1991 Aug,18:575-80. (PMID: 1877121)
[4] Agrons GA, Wagner BJ, Lonergan GJ, Dickey GE, Kaufman MS. Genitourinary rhabdomyosarcoma in children : Radiologic-Pathologic correlation. Radiographics. 1997;17:919-37. (PMID: 9225391)
Case information
| URL: | https://www.eurorad.org/case/1876 |
| DOI: | 10.1594/EURORAD/CASE.1876 |
| ISSN: | 1563-4086 |
Figure 2
Ultrasound of the bladder
A lobulated soft tissue mass is seen projecting into the bladder lumen at the level of the bladder base. The posterior bladder wall is thickened. (Different patient from Fig. 1).
A lobulated soft tissue mass is seen projecting into the bladder lumen at the level of the bladder base. The posterior bladder wall is thickened. (Different patient from Fig. 1).
Micturating cystourethrogram
Micturating cystourethrogram showing a lobulated filling defect in the posterior urethra. The bladder base is elevated.
Ultrasound of the bladder
A lobulated soft tissue mass is seen projecting into the bladder lumen at the level of the bladder base. The posterior bladder wall is thickened. (Different patient from Fig. 1).
A lobulated soft tissue mass is seen projecting into the bladder lumen at the level of the bladder base. The posterior bladder wall is thickened. (Different patient from Fig. 1).
