24 April 2026
: Case report 
Diagnostic and Treatment Strategies for Adult Non-Ossifying Fibromas: A Case Report and Literature Review
Challenging differential diagnosis, Congenital defects / diseases
Zhibin Zhao BE 1, Jiawei Li C 1, Shaoke Wu ABEFG 1*DOI: 10.12659/AJCR.951665
Am J Case Rep 2026; 27:e951665
Table 1 Discussion of strict differential diagnosis of large tibial epiphyseal lesions in adults.
| Disease | Lesion features |
|---|---|
| Giant cell tumor of bone (GCTB) | GCTB typically occurs in the epiphysis of long bones after physeal closure (ages 20–40), presenting as an eccentric, lytic lesion without sclerotic margins. While our patient’s age fits, the lesion location (proximal metaphysis rather than subchondral bone) and the presence of a well-defined sclerotic rim on imaging argued against GCTB, which usually lacks sclerotic borders. Additionally, MRI showed homogeneous signal intensity without the typical low-to-intermediate signal of GCTB on T1-weighted images |
| Aneurysmal bone cyst (ABC) | ABC commonly presents as an expansile, “blow-out” lytic lesion with cortical thinning. The characteristic fluid-fluid levels on MRI (due to internal hemorrhage and sedimentation) are diagnostic. In our case, MRI demonstrated solid tissue components with low signal on T1WI and PDWI, and no fluid-fluid levels were observed, making ABC unlikely |
| Fibrous dysplasia (FD) | FD typically manifests as a central, medullary lesion with a homogeneous “ground-glass” matrix and gradual cortical expansion. It often causes characteristic deformities (eg, “shepherd’s crook” deformity in the proximal femur). Our patient’s lesion was distinctly eccentric with sharp, sclerotic margins and lacked the ground-glass matrix, effectively ruling out FD |
| Low-grade malignant bone tumors | Desmoplastic fibroma and low-grade osteosarcoma were considered due to the lesion size and cortical disruption. However, the well-circumscribed, sclerotic border on imaging suggested a benign process. The absence of aggressive features (eg, a wide zone of transition, soft tissue mass with infiltration, or periosteal reaction) made malignancy less likely, although histological confirmation was mandatory to exclude these entities definitively |
| Non-ossifying fibroma (NOF) | Despite the patient’s atypical age (NOF usually occurs in children/adolescents), the lesion location (metaphysis of long bone), eccentric position, well-defined sclerotic margins, and the patient’s history of neurofibromatosis type 1 (NF1) supported NOF. NF1 is associated with persistent, large NOFs that may not regress and can present in adulthood |