PurposeThe purpose of this study was to assess the rate with which radiologists reported spinal epidural lipomatosis (SEL) when interpreting lumbosacral magnetic resonance imaging (MRI) examination. Materials and methodsA total of 450 lumbosacral MRI examinations obtained in 450 patients were included (199 men, 251 women; mean age, 56.7 ± 13.5 [SD] years; age range: 18–91 years). Three senior radiologists assessed and classified independently SEL on MRI according to the Borré grading system (Grade 1 to Grade 3). Depiction of SEL on MRI reports (i. e., reporting rate) and association with patients’ symptoms were verified. ResultsSEL was found in 75/450 patients (prevalence = 16.7%), and classified as grade-1 (mild) in 49/75 (65.3%) patients, grade-2 (moderate) in 24/75 (32%), and grade-3 (severe) in 2/75 (2.7%). SEL was diagnosed on MRI report in 6/75 (8%) patients. SEL prevalence based on MRI reports was 1.3% (6/450), significantly lower than its actual prevalence based on MRI examinations (P < 0.0001). The reporting rate was 0% in grade-1 (0/19), 10.2% in grade-2 (5/49) and 50.0% in grade-3 (1/2), and variable on the radiologist subspecialty (10.0% among musculoskeletal radiologists, 11.1% among neuroradiologists, and 3.7% among generalists). SEL was considered as the only cause of symptoms in 7/75 patients (9.3%) and a concurrent cause in 9/75 (12%). ConclusionSEL reporting rate is extremely low, leading to an important underestimation of disease prevalence. SEL diagnosis and grading should be refined to improve reports quality and subsequently patient care.