Intramedullary spinal cord metastases: MRI and relevant clinical features from a 13-year institutional case series

Abstract

Background and purpose: Because intramedullary spinal cord metastasis is often a difficult diagnosis to make, our purpose was to perform a systematic review of the MR imaging and relevant baseline clinical features of intramedullary spinal cord metastases in a large series.

Materials and methods: Consecutive patients with intramedullary spinal cord metastasis with available pretreatment digital MR imaging examinations were identified. The MR imaging examination(s) for each patient was reviewed by 2 neuroradiologists for various imaging characteristics. Relevant clinical data were obtained.

Results: Forty-nine patients had 70 intramedullary spinal cord metastases, with 10 (20%) having multiple intramedullary spinal cord metastases; 8% (4/49) were asymptomatic. Primary tumor diagnosis was preceded by intramedullary spinal cord metastasis presentation in 20% (10/49) and by intramedullary spinal cord metastasis diagnosis in 10% (5/49); 98% (63/64) of intramedullary spinal cord metastases enhanced. Cord edema was extensive: mean, 4.5 segments, 3.6-fold larger than enhancing lesion, and ≥3 segments in 54% (37/69). Intratumoral cystic change was seen in 3% (2/70) and hemorrhage in 1% (1/70); 59% (29/49) of reference MR imaging examinations displayed other CNS or spinal (non-spinal cord) metastases, and 59% (29/49) exhibited the primary tumor/non-CNS metastases, with 88% (43/49) displaying ≥1 finding and 31% (15/49) displaying both findings. Patients with solitary intramedullary spinal cord metastasis were less likely than those with multiple intramedullary spinal cord metastases to have other CNS or spinal (non-spinal cord) metastases on the reference MR imaging (20/39 [51%] versus 9/10 [90%], respectively; P = .0263).

Conclusions: Lack of known primary malignancy or spinal cord symptoms should not discourage consideration of intramedullary spinal cord metastasis. Enhancement and extensive edema for lesion size (often ≥3 segments) are typical for intramedullary spinal cord metastasis. Presence of cystic change/hemorrhage makes intramedullary spinal cord metastasis unlikely. Evidence for other CNS or spinal (non-spinal cord) metastases and the primary tumor/non-CNS metastases are common. The prevalence of other CNS or spinal (non-spinal cord) metastases in those with multiple intramedullary spinal cord metastases is especially high.

Fig 1.

Multiple intramedullary spinal cord metastases in an asymptomatic patient. A 73-year-old man with a history of metastatic lung adenocarcinoma underwent a spine MR imaging after a PET-CT scan had demonstrated multifocal spinal hypermetabolism. He was asymptomatic with regard to the spinal cord. Postcontrast sagittal T1-weighted images of the cervical (A) and thoracic (B) spine are shown. Multiple intramedullary spinal cord metastases are demonstrated at the C2, T4, T4–5, and T11 levels (arrows in A, B). In this series, several other patients were asymptomatic.

Fig 2.

Typical solitary intramedullary spinal cord metastasis, with visualization of primary tumor. A 66-year-old man presented with 6 weeks of paresthesias, bladder dysfunction, lower extremity weakness, and pain. Thoracic spine sagittal T2-weighted (A), sagittal T1-weighted (B), postcontrast sagittal T1-weighted (C), and axial T1-weighted (D) images are shown. A T2 hyperintense, expansile intramedullary cord lesion (arrow) is associated with a large amount of cord T2 hyperintensity (A). The mass is isointense on T1-weighted images (arrow in B) and enhances heterogeneously (arrow in C). Also noted is a left hilar lung mass (arrows in D), which was further evaluated with chest CT imaging (not shown). This hilar mass was pathologically proved to be a grade 4 undifferentiated small-cell lung carcinoma. Visualization on MR imaging of the primary tumor/non-CNS metastases and/or other spinal/CNS (non–spinal cord) metastases was common in this series.

Fig 3.

Multiple intramedullary spinal cord metastases, with visualization of other CNS metastases. A 60-year-old woman with a history of small-cell lung carcinoma, diagnosed 6.5 months prior, presented with several days of lower extremity weakness and urinary and stool incontinence. MR images of the cervical and thoracic spine with postcontrast fat-saturated consecutive sagittal T1-weighted images of the thoracic spine (A, B, C) and postcontrast sagittal T1-weighted image of the cervical spine (D) are shown. Several enhancing intramedullary lesions are present (white arrows in A, B, D). There is abnormal leptomeningeal enhancement with several small metastases studding the surface of the cord (arrows in C). Metastases are visualized in the lower pons and cerebellum (thick white arrows in D). Visualization on MR imaging of other CNS or spinal (non-spinal cord) metastases was common in this series, and more common in patients with multiple ISCMs.

Fig 4.

Atypical intramedullary spinal cord metastasis with central cystic change/necrosis. A 55-year-old man with recent nephrectomy of a renal cell carcinoma presented with 2 weeks of predominantly left upper extremity pain, paresthesias, and weakness, as well as global hyperreflexia. Cervical spine sagittal T2-weighted (A), T1-weighted (B), and postcontrast fat-saturated T1-weighted images (C), and postcontrast axial T1-weighted image are shown. A mass within the cord at the level of C5 has markedly hyperintense central signal on T2-weighted imaging (A) and corresponding T1 hypointensity (B) consistent with central cystic change/necrosis. The sagittal (C) and axial (D) T1-weighted postcontrast images demonstrate the peripheral enhancement with lack of central enhancement corresponding to the region of central cystic/necrotic change. This represents 1 of only 2 cases in the current series of intramedullary spinal cord metastasis demonstrating cystic/necrotic change. The primary tumor type in the other case (not shown) was lung carcinoma.

Fig 5.

Atypical intramedullary spinal cord metastasis with associated hemorrhage. A 74-year-old man with squamous cell carcinoma of the lung diagnosed 2 years prior presented with 4 weeks of paraplegia. Thoracic spine shown with sagittal T1-weighted (A) and T2-weighted (B) and axial gradient recalled-echo (C) images. Heterogeneous mildly hyperintense central signal is present within the intramedullary spinal cord metastasis on T1-weighted imaging (arrows in A). There is corresponding heterogeneity on T2-weighted imaging (B). The axial gradient recalled-echo image demonstrates corresponding central hypointensity (“blooming,” arrow in C), typical of hemorrhage. This is the only intramedullary spinal cord metastasis in the current series demonstrating signal changes convincing for associated hemorrhage.