Bilateral Lung Metastases From a Phalangeal Giant Cell Tumor of Bone.

We describe a rare pediatric case of a phalangeal giant cell tumor of bone with extensive bilateral lung metastases following curettage, wide resection, and amputation. Concurrent peripheral blood eosinophilia and pleural effusion with marked eosinophilia (47%) were present. To discover genetic changes driving tumor metastasis, genomic and transcriptome profiling of the metastatic lung mass as well as germline analysis were performed.