Article Figures & Data
Figures
- Fig. 1.
Rim sign. A 56-year-old woman with metastatic ovarian adenocarcinoma who presented to the emergency department with progressive lower extremity weakness and intermittent urinary retention. MR imaging of the thoracic spine demonstrates intramedullary spinal cord metastasis at T8–9. Sagittal T2-weighted (A), T1-weighted (B), postcontrast T1-weighted (C), and axial postcontrast T1-weighted (D) images. Note the rim sign (arrows, C and D): an enhancing intramedullary mass with a thin rim of more intense enhancement.
- Fig. 2.
Flame sign. A 55-year-old man with metastatic small cell lung carcinoma who presented with severe midback pain, progressive weakness, and altered sensation in both lower extremities. MR imaging of the thoracic spine demonstrates intramedullary spinal cord metastasis at T3–4. Sagittal T2-weighted (A), T1-weighted (B), and postcontrast T1-weighted (C) images. Note the flame sign (arrow, C): an ill-defined flame-shaped region of enhancement at the inferior margin of the otherwise well-defined mass.
- Fig. 3.
Concurrent rim and flame signs. A 68-year-old man with metastatic non-small cell lung carcinoma who presented with progressive bilateral lower extremity weakness. MR imaging of the cervical spine demonstrates an intramedullary spinal cord metastasis at C6. Sagittal T2-weighted (A), T1-weighted (B), and postcontrast T1-weighted fat-suppressed (C) images. Note the enhancing intramedullary mass with a thin rim of more intense enhancement (rim sign; black arrows, C) as well as the ill-defined flame-shaped regions of enhancement at the superior and inferior margins of the mass (flame sign; white arrows, C).
- Fig. 4.
Pathologically proved intramedullary spinal cord metastasis demonstrating the potential utility of the rim and flame signs. A 55-year-old man who presented with 8 months of progressive lower extremity paresthesias. MR imaging of the thoracic spine demonstrates an intramedullary spinal cord metastasis due to small cell lung carcinoma. Sagittal T2-weighted (A), T1-weighted (B), postcontrast T1-weighted (C), and axial T2-weighted (D) images. Note the concurrent rim (black arrows, C) and flame signs (white arrows, C). Despite these findings and the observation of a small right upper lobe mass (small white arrow, D), the radiologist's primary consideration was ependymoma. The clinicians agreed with this impression. Bronchoscopic biopsy of mediastinal adenopathy yielded small cell carcinoma. Because of the impression of the cord mass being an ependymoma, a diagnostic partial resection was performed, yielding metastatic small cell carcinoma. Knowledge of the rim and flame signs as specific findings of ISCM could potentially have avoided diagnostic biopsy.
- Fig. 5.
Rarity of rim and flame signs in primary cord masses. Only 4 primary cord masses demonstrated 1 of the signs, all shown here; none displayed both signs. Axial postcontrast T1-weighted image (A) in a 70-year-old man with a hemangioblastoma with a partial rim sign (arrows). Sagittal postcontrast T1-weighted images in a 20-year-old woman (B) with a thoracic hemangioblastoma with a partial rim sign (arrows), a 26-year-old man (C) with a thoracic WHO grade II ependymoma with a flame sign superiorly (arrow), and a 21-year-old man (D) with a cervicothoracic WHO grade I pilocytic astrocytoma with a flame sign inferiorly (arrow).
Tables
- Table 1:
Enhancement characteristics of intramedullary spinal cord metastases and primary masses (per-lesion basis)
Intramedullary Spinal Cord Metastases (n = 64) Primary Spinal Cord Masses (n = 64) Ependymoma (n = 21) Astrocytoma (n = 21) Hemangioblastoma (n = 11) Ganglioglioma (n = 5) Cavernous Malformation (n = 6) No enhancement 1 (2%) 10 (16%) 0 6 (29%) 0 1 (20%) 3 (50%) Rim sign 21 (33%) 2 (3%) 0 0 2 (18%) 0 0 Flame sign 19 (30%) 2 (3%) 1 (5%) 1 (5%) 0 0 0 Rim without flame sign 9 (14%) 2 (3%) 0 0 2 (18%) 0 0 Flame without rim sign 7 (11%) 2 (3%) 1 (5%) 1 (5%) 0 0 0 Only rim or flame signa 16 (25%) 4 (6%) 1 (5%) 1 (5%) 2 (18%) 0 0 Both rim and flame signs 12 (19%) 0 0 0 0 0 0 At least rim or flame signb 28 (44%) 4 (6%) 1 (5%) 1 (5%) 2 (18%) 0 0 Rim Sign Only Flame Sign Only Both Signs Neither Sign At Least One Sign All ISCMs (n = 45) 9 (20%) 6 (13%) 12 (27%) 18 (40%) 27 (60%) Lung carcinoma (n = 22) 6 (27%) 3 (14%) 8 (36%) 5 (23%) 17 (77%) Breast carcinoma (n = 6) 0 0 1 (17%) 5 (83%) 1 (17%) Melanoma (n = 5) 0 1 (20%) 1 (20%) 3 (60%) 2 (40%) CNS origin (n = 4) 0 0 0 4 (100%) 0 Renal cell carcinoma (n = 2) 0 1 (50%) 1 (50%) 0 2 (100%) Other (n = 6) 3 (50%) 1 (17%) 1 (17%) 1 (17%) 5 (83%) ISCM identified prior to systemic metastatic disease diagnosis (n = 10) 3 (30%) 2 (20%) 4 (40%) 1 (10%) 9 (90%) Radiation therapy for primary malignancy included relevant spinal cord (n = 5) 0 1 (20%) 3 (60%) 1 (20%) 4 (80%) Ongoing systemic steroid therapy at time of MRI (n = 12) 2 (17%) 2 (17%) 3 (25%) 5 (42%) 7 (58%)
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