osteoblastoma

noun
os·​teo·​blas·​to·​ma | \ -bla-ˈstō-mə How to pronounce osteoblastoma (audio) \
plural osteoblastomas also osteoblastomata\ -​mət-​ə How to pronounce osteoblastomata (audio) \

Medical Definition of osteoblastoma

: a benign tumor of bone