Multifocal and Diffuse Spinal Lesions That May Mimic Metastases

Metastases are a relatively frequent cause of multifocal or diffuse lesions in the spine that can affect the vertebral cortex and/or marrow and trabecular bone. Metastases appearance can be variable, and metastases that predominantly affect the bone marrow may only be visible on MR imaging. Notably, a number of nonneoplastic processes can present with overlapping imaging features that may be misinterpreted as metastases, particularly in patients who have a primary malignancy. Evaluation might be particularly challenging for those lesions that primarily affect the bone marrow because this organ experiences continued physiologic and reactive changes that alter its appearance on MR imaging. In this review, we present a spectrum of physiologic and benign conditions that show multifocal or diffuse spinal lesions, including age-related changes, benign vascular neoplasms, inflammatory diseases, hemoglobinopathies, syndromic entities, metabolic syndromes, and postradiation changes, focus on their imaging characteristics, and emphasize potential pitfalls in the diagnosis. We classify these lesions into those that produce trabecular or cortical changes with a lucent, sclerotic, or mixed appearance on CT and those without significant CT abnormalities that are predominantly or exclusively seen on MR imaging. Differentiating these entities from metastases is critical so that the correct treatment can be given.

Learning Objective: To identify various causes of multifocal and diffuse lesions in the spine and bone marrow changes that may simulate metastases and to recognize characteristic imaging features.