Epigenetic lockdown of CDKN1A (p21) and CDKN2A (p16) characterises the neoplastic spindle cell component of giant cell tumours of bone.

Giant cell tumour of bone (GCTB) comprises the eponymous osteoclastic multinucleated giant cells eliciting bone lysis, an H3F3A-mutated neoplastic mononucleated fibroblast-like cell population, and H3F3A wild-type mononucleated stromal cells. In this study, we characterised four new cell lines from GCTB. Furthermore, we compared the genome-wide DNA methylation profile of 13 such tumours and three further cell lines with giant cell-rich lesions comprising three H3F3B-mutated chondroblastomas, three USP6-rearranged aneurysmal bone cysts, three non-ossifying fibromas, two hyperparathyroidism-associated brown tumours as well as mesenchymal stem cells, osteoblasts, and osteoclasts.

[H3F3A mutated multicentric giant cell tumor of bone : A very rare primary bone disease].

This article presents the case of a metachronic multicentric giant cell tumor of bone (GCTB). The patient obtained his first diagnosis of GCTB in the left humerus at the age of 47 years. Furthermore, he suffered from a GCTB in the head of his 4th left metacarpal bone and from a recurrence of the latter.