How would you manage a child with subtotal resection of an atypical choroid plexus papilloma?

Data from the SickKids Hospital study strongly suggest that the extent of resection is prognostic in atypical CPP, and in the presence of GTR, chemotherapy may be avoided or skipped entirely (Browne-Farmer et al., PMID 34529227). The role of adjuvant treatment in the setting of incompletely resected M0 atypical CPP is, however, unclear. The SIOP data with a small number of patients provides some insight into his situation (Wolff et al., PMID 34997889). Of the 4 patients with aCPP that were observed, 2 had relapse but were successfully salvaged with chemoradiotherapy, while the remaining 5 received upfront chemotherapy and were alive with no events. While careful observation without adjuvant chemotherapy in this situation may be reasonable, ...

I agree with Santhosh. There are anecdotal cases of transformation into CPC, and staining for p53 is recommended. Otherwise, observation is an option. Of course, if the surgeon feels that he/she can resect the residual, this is the first and best option. I agree that the role of chemotherapy is still unclear, but the data from Wolff et al., PMID 34997889 suggests that some aCPP patients seem to benefit from chemo. It should not be intensive chemo. Etoposide and carboplatin are an option. I would not consider radiation, particularly if the child is young.