Rare anaplastic sarcoma of the kidney: A case report

Anaplastic sarcoma of the kidney (DICER1-sarcoma of the kidney): A report from the International Pleuropulmonary Blastoma/DICER1 Registry

BACKGROUND

Anaplastic sarcoma of the kidney (ASK) is a DICER1-related neoplasm first identified as a distinctive tumor type through the evaluation of unusual cases of putative anaplastic Wilms tumors. Subsequent case reports identified the presence of biallelic DICER1 variants as well as progression from cystic nephroma, a benign DICER1-related neoplasm. Despite increasing recognition of ASK as a distinct entity, the optimal treatment remains unclear.

METHODS

Individuals with known or suspected DICER1-related tumors including ASK were enrolled in the International Pleuropulmonary Blastoma/DICER1 Registry. Additionally, a comprehensive review of reported cases of ASK was undertaken, and data were aggregated for analysis with the aim to identify prognostic factors and clinical characteristics to guide decisions regarding genetic testing, treatment, and surveillance.

RESULTS

Ten cases of ASK were identified in the Registry along with 37 previously published cases. Staging data, per Children's Oncology Group guidelines, was available for 40 patients: 13 were stage I, 12 were stage II, 10 were stage III, and five were stage IV. Outcome data were available for 37 patients. Most (38 of 46) patients received upfront chemotherapy and 14 patients received upfront radiation. Two-year event-free survival (EFS) for stage I-II ASK was 81.8% (95% confidence interval [CI]: 67.2%-99.6%), compared with 46.6% EFS (95% CI: 24.7%-87.8%) for stage III-IV (p = .07). Two-year overall survival (OS) for stage I-II ASK was 88.9% (95% CI: 75.5%-100.0%), compared with 70.0% (95% CI: 46.7%-100.0%) for stage III-IV (p = .20). Chemotherapy was associated with improved EFS and OS with hazard ratios of 0.09 (95% CI: 0.02-0.31) and 0.08 (95% CI: 0.02-0.42), respectively.

CONCLUSION

ASK is a rare DICER1-related renal neoplasm. In the current report, we identify clinical and treatment-related factors associated with outcome including the importance of chemotherapy in treating ASK. Ongoing data collection and genomic analysis are indicated to optimize outcomes for children and adults with these rare tumors.

Anaplastic Sarcoma of the Kidney With Heterologous Ganglioneuroblastic Differentiation: Another DICER1-Associated Tumor

Anaplastic sarcoma of the kidney (ASK) is a rare renal tumor for which less than thirty cases have been described in the literature to date. Diagnosis of ASK is primarily based on histology, which features solid spindle cell neoplastic islands arranged in a fascicular pattern, prominent anaplastic nuclear morphology, brisk mitoses, and multiple multiloculated cysts lined by hobnail epithelium reminiscent of cystic nephroma. Chondroid or rhabdomyocytic differentiation is often present within the sarcoma. It has been recently suggested that this tumor entity belongs to the DICER1 syndrome tumors based on identification of DICER1 mutations. We report on a case of this rare tumor found in a twenty-month-old female. In addition to the typical histologic findings of ASK, this case also displayed heterologous neuroblastic-gangliocytic differentiation, which has not been previously described in the literature. TP53 and BRAF v600E had aberrant immunostaining. Chromosomal microarray and genomic sequencing revealed loss of chromosome 10 p15.3-p11.2 and both somatic and germline DICER1 mutations, consistent with recent research and further supporting the classification of this tumor within the DICER1 syndrome associated tumors.