Edema-like marrow signal intensity (ELMSI) associated with nonossifying fibroma (NOF) on MRI: an uncommon finding in a common bone lesion

Skeletal Radiol. 2023 Aug;52(8):1511-1518. doi: 10.1007/s00256-023-04312-9. Epub 2023 Mar 3.


Objective: To investigate the association between nonossifying fibroma (NOF) and perilesional edema-like marrow signal intensity (ELMSI) on MRI and discuss the clinical and diagnostic implications of this finding.

Materials and methods: A retrospective search for "nonossifying fibroma" and "NOF" on knee MRI reports of patients up to 20 years of age over a 5-year period was performed. A total of 77 patients (34 males, 43 females, ages 11-20) were identified, and each MRI was reviewed to evaluate for ELMSI associated with the NOF. Statistical analysis was performed to determine if there was a correlation with the presence of perilesional ELMSI and age, gender, lesion size, or signal characteristics.

Results: Twelve patients out of 77 (16%) had ELMSI associated with a NOF. Excluding patients who had additional findings of pathologic fracture (n = 2), a known potential complication of NOFs, and edema related to an adjacent osteoid osteoma (n = 1), a total of 9 patients (12%) had otherwise unexplained perilesional ELMSI. There was no statistically significant difference between patients with vs. without perilesional ELMSI with respect to age (p = 0.08), gender (p = 0.28), lesion size (p = 0.52), or appearance on fluid-sensitive sequences (p = 0.81).

Conclusion: ELMSI can be seen about NOFs encountered around the knee joint on MRI, which may represent active healing and/or involutional change of this "do not touch" lesion in cases where no other explanation is identified.

Keywords: Bone marrow edema; Edema-like marrow signal intensity (ELMSI); MRI; NOF; Nonossifying fibroma.

MeSH terms

  • Bone Marrow / diagnostic imaging
  • Bone Marrow / pathology
  • Bone Neoplasms* / complications
  • Bone Neoplasms* / diagnostic imaging
  • Edema / complications
  • Edema / diagnostic imaging
  • Female
  • Fibroma* / diagnostic imaging
  • Fibroma* / pathology
  • Humans
  • Magnetic Resonance Imaging / methods
  • Male
  • Retrospective Studies