MRI features of metastases that involve the brachial plexus

Secondary tumors involving the brachial plexus are more common than primary tumors. Breast and lung cancer are the most common cancers that involve the brachial plexus.Lymphoma, melanoma, squamous cell carcinomas arising in the head and neck, and malignant mesotheliomas are some of the tumors that metastasize to the axillary nodes and involve the plexus. Typically, metastases from all causes have low signal intensity (SI) on T1W images and a high SI on T2W images, relative to the signal of muscle

.. Metastases show enhancement on gadolinium-enhanced images. Occasionally they may demonstrate low SI on T2W images.In cases of lymphoma, enlarged nodes can either directly compress the plexus or infiltrate it . Neurolymphomatosis is a rare manifestation of lymphoma that predominantly involves the peripheral nerves and can involve the brachial plexus. MRI shows diffuse thickening of the plexus components, with marked T2 hyperintensity and postcontrast enhancement

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A 71-year-old male with buccal squamous cell carcinoma and supraclavicular lymph node metastasis. The coronal T1W (A) image shows a low-signal-intensity metastatic lymph nodal mass compressing the trunks, divisions, and cords of the right brachial plexus (arrow). On the corresponding coronal T2W (B) image, the mass shows high intensity (arrow)