Primary lymphoma of bone is a rare malignancy that can mimic infection and benign bone lesions radiographically. Malignant conversion of osseous lesions has been reported; evolution to lymphoma has not. We describe an adolescent male diagnosed with atypical osteoid osteoma who, despite near resolution of bony changes involving the anterior tibia, was diagnosed with monostotic diffuse large B-cell lymphoma four years later. Indolent lymphoma of the initial lesion is unlikely. This case highlights the importance of clinical suspicion of malignancy even with recurrence of similar clinical presentation and hints at possible osseous microenvironment abnormalities predisposing to the development of lymphoma. Pediatr Blood Cancer 2013;60:E113–E115. © 2013 Wiley Periodicals, Inc.