One of the challenges faced when treating a child with genitourinary rhabdomyosarcoma is what to do when a residual mass remains after organ sparring treatment. The authors present an interesting case which exemplifies the dilemma. The answer to this question is simplified for when the residual mass is associated with pain, is growing or impairs organ function, providing a rational for excision. When this is not the case concern centers around residual disease and recurrence. Today the post-treatment finding of mature rhabdomyoblasts is not a reason for exenterative surgery, however some point bear mentioning. 1)Post-treatment pathology is difficult to interpret. In a review of IRS IV patients Arndt et al reported that in 16 of 42 cases reviewed, the interpretation of the children's oncology group study pathologist disagreed with that of the local pathologist. 1 Arndt CA Hammond S Rodeberg D Qualman S Significance of persistent mature rhabdomyoblasts in bladder/prostate rhabdomyosarcoma: results from IRS IV. J Pediatr Hematol Oncol. 2006; 28: 563-567 Crossref PubMed Scopus (27) Google Scholar These errors occurred in both directions, over and under calling active tumor. Thus, the interpretation of “only rhabdomyoblasts” should be made by an experienced pathologist and second review maybe helpful. 2)Variations in terminology create confusion. The many different ways in which post-treatment pathology is reported including, differentiated Rhabdomyosarcoma (RMS), post-chemo RMS, treated RMS… are a source of confusion when reviewing the literature or managing individual patients. There are precise histologic and immunohistochemical criteria associated with mature rhabdomyoblasts. 3)The literature varies regarding immunohistochemical profile. In their children's oncology group based analysis Arndt et al that “the fully mature rhabdomyoblasts lose their positivity for myogenin and myo-D1.” In 2006 Godbole et al in a report from Great Ormond Street noted that in post-treatment specimens more differentiated rhabdomyoblasts were highlighted by myogenin staining. 2 Godbole P Outram A Wilcox DT Duffy PG Sebire NJ Myogenin and desmin immunohistochemistry in the assessment of post-chemotherapy genitourinary embryonal rhabdomyosarcoma: prognostic and management implications. J Urol. 2006; 176: 1751-1754 Crossref PubMed Scopus (5) Google Scholar Variations in timing of biopsy/resection, whether the specimen was obtained before or after radiation, among other factors may impact IHC results.