Romanus and Andersson Lesions¶

Romanus Lesions¶

Romanus lesions are inflammatory erosions at the anterior corners of the vertebral bodies in ankylosing spondylitis. They represent the earliest spinal manifestation of AS on MRI.

Acute (Active) Romanus Lesion¶

MRI — High STIR/T2 signal at the anterior vertebral body corners ("shiny corners"), representing bone marrow edema from active enthesitis
Pathology — Active inflammation at the insertion of the annulus fibrosus into the vertebral endplate

Chronic (Healed) Romanus Lesion¶

MRI — High T1 signal at the anterior corners, representing fatty marrow replacement (post-inflammatory fatty change)
Radiography/CT — Erosion and sclerosis at the anterior corners, leading to "squaring" of the vertebral body as the normal anterior concavity is lost

Clinical Pearl

The "shiny corner" sign — bright STIR signal at the anterior vertebral body corners — is the earliest MRI finding of spinal involvement in AS and often precedes syndesmophyte formation by years. Recognizing this sign can lead to earlier diagnosis in young patients with inflammatory back pain and normal radiographs.

Andersson Lesions¶

Andersson lesions (discovertebral lesions) are destructive lesions at the discovertebral junction in patients with ankylosing spondylitis. They can mimic spondylodiscitis or pathological fracture.

Types¶

Inflammatory Andersson lesion — An extension of the inflammatory enthesopathy into the discovertebral junction, causing erosion and edema on both sides of the disc. Represents active inflammation.
Mechanical Andersson lesion (pseudarthrosis) — A stress fracture/pseudarthrosis through a fused spinal segment, typically at the thoracolumbar junction. Occurs because of abnormal stress concentration at a non-fused or incompletely fused segment within an otherwise rigid spine.

Imaging¶

MRI — Bone marrow edema (low T1, high STIR) at the endplates on both sides of a disc, with possible disc signal abnormality. Can closely mimic infectious spondylodiscitis.
CT — Endplate irregularity, erosions, sclerosis. May show vacuum phenomenon in a pseudarthrosis.
Key distinction from infection — Clinical context (known AS, no fever, normal inflammatory markers) and imaging pattern (within a fused spine, no paravertebral abscess) help distinguish from infection.

Key Points¶

Romanus lesions are the earliest spinal MRI finding in AS — "shiny corners" on STIR
Chronic Romanus lesions produce vertebral body squaring from erosion and fatty replacement
Andersson lesions can be inflammatory or mechanical (pseudarthrosis)
Andersson lesions can closely mimic spondylodiscitis — clinical context is essential
MRI with STIR is the key modality for detecting active inflammatory lesions

References¶

Hermann KGA, Althoff CE, Schneider U, et al. Spinal changes in patients with spondyloarthritis: comparison of MR imaging and radiographic appearances. RadioGraphics. 2005;25(3):559-69; discussion 569-70. https://pubs.rsna.org/doi/full/10.1148/rg.253045117
Bron JL, de Vries MK, Snieders MN, van der Horst-Bruinsma IE, van Royen BJ. Discovertebral (Andersson) lesions of the spine in ankylosing spondylitis revisited. Clin Rheumatol. 2009;28(8):883-92. https://pmc.ncbi.nlm.nih.gov/articles/PMC2711912/
Canella C, Schau B, Ribeiro E, Sbaffi B, Marchiori E. MRI in seronegative spondyloarthritis: imaging features and differential diagnosis in the spine and sacroiliac joints. AJR Am J Roentgenol. 2013;200(1):149-57. https://pubmed.ncbi.nlm.nih.gov/23255756/
Østergaard M, Lambert RGW. Imaging in ankylosing spondylitis. Ther Adv Musculoskelet Dis. 2012;4(4):301-11. https://pmc.ncbi.nlm.nih.gov/articles/PMC3403247/
de Vries MK, van Drumpt AS, van Royen BJ, van Denderen JC, Manoliu RA, van der Horst-Bruinsma IE. Discovertebral (Andersson) lesions in severe ankylosing spondylitis: a study using MRI and conventional radiography. Clin Rheumatol. 2010;29(12):1433-8. https://pubmed.ncbi.nlm.nih.gov/20496041/
Wenker KJ, Quint JM. Ankylosing Spondylitis. In: StatPearls. Treasure Island (FL): StatPearls Publishing; updated 2023 Jun 20. https://www.ncbi.nlm.nih.gov/books/NBK470173/
Romanus lesion (vertebral bodies). Radiopaedia.org. https://radiopaedia.org/articles/romanus-lesion-vertebral-bodies
Andersson lesion. Radiopaedia.org. https://radiopaedia.org/articles/andersson-lesion-1