# Malignant melanoma in a 12‐year‐old boy 17 months after completing hepatoblastoma treatment

## TL;DR

A 12-year-old boy developed melanoma 17 months after being treated for hepatoblastoma, but no genetic link between the two cancers was found.

## Contribution

This case study reports a rare instance of melanoma following hepatoblastoma treatment in a child without identifying a genetic predisposition.

## Key findings

- Melanoma occurred 17 months after hepatoblastoma treatment in a 12-year-old boy.
- Immune checkpoint inhibitor therapy was ineffective, and the patient died within 6 weeks.
- Whole-exome sequencing found no germline variants linked to cancer predisposition.

## Abstract

Melanoma is rare as a secondary malignant neoplasm among childhood cancer survivors.

We report a case of a 12‐year‐old boy who developed malignant melanoma with systemic metastases 17 months after completing treatment for hepatoblastoma. The diagnosis was made unexpectedly based on a bone marrow examination. The patient did not respond to immune checkpoint inhibitor therapy and died 6 weeks after being diagnosed with melanoma. Whole‐exome sequencing to examine 103 genes associated with cancer predisposition did not identify any germ‐line variants.

This case study provides a unique example of melanoma in a childhood cancer survivor following hepatoblastoma treatment but does not identify any candidate variant to link hepatoblastoma and melanoma.