From the Archives of the AFIP: Genitourinary Rhabdomyosarcoma in Children

Radiologic-Pathologic Correlation

Abstract Introduction Clinical Features

Pathologic Features Radiologic Features Differential Diagnosis Treatment and Prognosis

Summary Source Information References

Treatment and Prognosis

Whenever possible, surgical excision remains the initial treatment of choice. For paratesticular rhabdomyosarcoma, an inguinal surgical approach with resection of the spermatic cord and testis is favored because this method is associated with a lower rate of local recurrence compared with a transscrotal approach. Nonparatesticular genitourinary rhabdomyosarcoma presents a greater therapeutic challenge. In these cases, surgical resection and high-dose radiation therapy are effective but may result in unacceptable damage to vital organs and compromise of bodily functions. In a review of 86 children with rhabdomyosarcoma enrolled in the First and Second Intergroup Rhabdomyosarcoma Studies, long-term health problems related to surgery included bowel obstruction, loss of normal ejaculatory function, hydrocele, and lymphedema of the leg (40). Sequelae of radiation therapy included chronic diarrhea, urethral stricture, and bone or soft-tissue hypoplasia in the radiation field. Hemorrhagic cystitis and gonadal dysfunction were the primary adverse effects of chemotherapy.

Current multidisciplinary treatment protocols attempt to optimize the contributions of chemotherapy, radiation therapy, and surgery while minimizing the damage to pelvic structures. Ideally, surgical resection is delayed until the primary tumor is reduced in size by chemotherapy. In girls with early stage vulvovaginal rhabdomyosarcoma, for instance, total pelvic exenteration and the adverse effects of radiation therapy can be avoided by the use of preoperative systemic chemotherapy (41). In addition, the ascendancy of chemotherapy in the management of rhabdomyosarcoma has obviated abdominal lymph node dissection in many clinical centers. However, the need for debulking large nodal metastases remains controversial (42,43).

In general, the prognosis of children with rhabdomyosarcoma has improved dramatically in the past 2 decades. The dismal survival rates of 10% 20% in the past have risen steadily to 73% for patients included in the Third Intergroup Rhabdomyosarcoma Study (3). This improvement is attributable to combined treatment with chemotherapy, radiation therapy, and surgery. In particular, significantly more children with rhabdomyosarcoma are surgical candidates due to shrinkage of the primary tumor by chemotherapy or radiation therapy before resection.

Survival rates for children with rhabdomyosarcoma vary with the anatomic site and stage of the primary tumor. Because of early detection and surgical accessibility, paratesticular rhabdomyosarcoma has a relatively good prognosis, with 3-year survival rates of 73% 89% (2). The prognosis for children with nonparatesticular genitourinary rhabdomyosarcoma is not as favorable; according to the Second Intergroup Rhabdomyosarcoma Study, the 3-year survival rate for these patients was 64% (44). Stage IV disease has proved to be most refractory. Relapse in any location is a poor prognostic sign, and patients with recurrent disease have a 2-year survival rate of only 17% (3).

The response to initial chemotherapy or radiation therapy is monitored with CT or MR imaging, and the frequency and scope of follow-up imaging of the residual mass are guided by an understanding of the natural history of rhabdomyosarcoma based on anatomic site and stage (7). In general, local recurrence of rhabdomyosarcoma is common, with or without concurrent metastatic spread (12). However, paratesticular rhabdomyosarcoma has a low rate of relapse, whereas rhabdomyosarcoma in other genitourinary sites has a significant recurrence rate, and the frequency of radiologic surveillance should be modified accordingly. In addition, it is important to recognize that although relapse in stage I disease is less common than in stage IV disease, it does occur. Thus, follow-up imaging of patients with stage I rhabdomyosarcoma is required. Finally, the use of radiation therapy in virtually all patients with rhabdomyosarcoma (except for those with stage I lesions of nonalveolar histologic characteristics) has important implications for radiologic follow-up (7). For example, soft-tissue edema representing postirradiation changes should be anticipated on CT and MR images and not mistaken for tumor spread; similarly, abnormality of bone marrow signal intensity on MR images may be caused by radiation therapy not tumor (Figure 3).

Abstract Introduction Clinical Features

Pathologic Features Radiologic Features Differential Diagnosis Treatment and Prognosis

Summary Source Information References