Discussion
MiT-family translocation RCC has TFE3 on chromosome Xp11.2 and
the transcription factor EB gene on chromosome 6p21 as the major
translocated genes. It was also
reported that approximately 15% of these cases have a history of
chemotherapy in childhood.1 Our case was suspected of
being associated with prior chemoradiotherapy. SMN after nephroblastoma
treatment is widely known; for example, brain tumors, single
retinoblastoma, and basal cell carcinoma. RCC is relatively rare as a
SMN after nephroblastoma treatment, and only 4 of 13,351 patients were
found to have RCC in a recent multi-institutional
report.2 In our review of 11 previously reported cases
of secondary RCC after nephroblastoma treatment as well as our own study
(Table 1), only 2 cases, including our own study, were diagnosed as
translocation RCC.1 Eight cases were clear cell
RCC3–9, one case was papillary cell
RCC10, and one case had an unspecified histologic
type. Our review included only two cases of translocation RCC, although
this number might be underestimated. This is because translocation RCC
was first classified in the 2004 World Health Organization
classification of renal tumors; prior cases were impossible to diagnose,
and diagnosis of TFE3 translocation RCC may be inaccurate in
facilities that cannot perform the TFE3 break-apart FISH
technique.11
The appropriate course of action for this clinical case was difficult to
determine because of suspected metastasis. For a single metastatic RCC
suspected in the left eighth rib, cytoreductive partial nephrectomy and
resection of the metastases, or systemic therapy after tissue diagnosis
by renal biopsy, are viable treatment options. However, given that this
is a single kidney case, needle renal biopsy is a high-risk option.
Additionally, there is insufficient evidence supporting the efficacy of
immune checkpoint inhibitors or tyrosine kinase inhibitors for
metastatic translocation RCC. In our review, the longest recurrence-free
period of RCC after surgery was 22 months.4Considering the need to preserve renal function, enhance the precision
and safety of histological analysis, and ensure curative potential,
partial nephrectomy was deemed the preferable option.
In our review (Table 1), six cases underwent partial nephrectomy as
surgical treatment. No reports of severe acute renal failure were
observed during the operative period. These findings suggest that
partial nephrectomy is also valuable in treating secondary RCC after
nephroblastoma treatment with regards to preservation of renal function.