Fetal Rhabdomyomatous Nephroblastoma: Report of 14 Cases Confirming Chemotherapy Resistance

Abstract

The authors retrospectively reviewed their experience with 14 cases of fetal rhabdomyomatous nephroblastoma (15.6% of all renal tumors seen in the 1984-1998 period), analyzing the diagnostic and treatment approach as well outcome. Mean age at presentation was 27 months; 10 (71%) patients were younger than 36 months (5 of these were less than 12 months) at diagnosis. Three patients had bilateral tumors. One case was extrarenal. Nine patients received preoperative chemotherapy after fine-needle aspiration biopsy. The response was null in five children and mild in three; in the remaining one the tumor increased in size. The only patient showing greater than 50% tumor shrinkage was the one treated with radiotherapy. Postoperative treatment according to staging followed the SIOP protocol. In the follow-up (mean 59.5 months) of 12 patients, 6 were in stages 1-2: 4 are alive and free of disease and 2 died (one due to intractable local recurrence and the other in complete clinical remission). All six patients presenting in advanced stages died (four due to disease progression and two due to complications while in complete clinical remission). Patients with fetal rhabdomyomatous nephroblastoma presenting with distant metastatic disease and high stage have unfavorable outcomes, confirming data from the literature indicating that chemotherapy is not as effective as in other variants of nephroblastoma. New protocols are needed to overcome this situation, for which surgery appears the only truly effective option.

Rhabdomyoblastic pulmonary lesions in a patient with Wilms Tumor: choristomas or metastases?

“…It may also be possible to explain the histologic features of the lung nodules as part of the spectrum of the fetal rhabdomyomatous variant of WT (FRWT), which has been described in several recent reports 11,12. NWTS‐4 reported 35 cases in 2,077 patients (1.8%) of this rare variant.…”

Rhabdomyoblasts in Pediatric Tumors: A Review with Emphasis on their Diagnostic Utility

“…Skeletal muscle in various stages of differentiation, including rhabdomyoblasts ( Figure 1B, C) represents the most common divergent line of differentiation [23]. Rare cases of WT showing diffuse and predominant rhabdomyoblastic differentiation have been reported in the literature under the descriptive term of fetal rhabdomyomatous nephroblastoma [24]. This exceedingly rare variant of Wilms' tumour shows little or no response to preoperative chemotherapy and is associated with a generally favourable outcome in most of all unilateral cases when treated by surgery.…”

Wilms Tumor

“…1). 10,11 ANAPLASIA Several large studies have demonstrated that the presence of anaplasia in WT is associated with lack of response to chemotherapy with an adverse outcome. 2).…”