From the Research
Imaging Tests for Metastatic Melanoma
- The best imaging test for a patient with a history of metastatic melanoma presenting with lower extremity weakness is Contrast MRI 1, 2.
- Contrast MRI is the diagnostic modality of choice for diagnosing intramedullary spinal cord metastasis (ISCM) secondary to melanoma, as it has higher sensitivity compared to non-contrast MRI 1.
- MRI with contrast can help identify enhancing soft tissue metastatic mass lesions within the conus, which may not be visible on plain MRI 1.
- Other imaging modalities such as Positron Emission Tomography-Computed Tomography (PET/CT) can be useful in evaluating the extent of local and metastatic disease 2, 3.
- However, PET/CT imaging of the lower extremity may not be justified if the primary neoplasm is not located in the lower extremities, and elimination of lower extremity imaging can reduce scanning time and additional radiation exposure 3.
Characteristics of Metastatic Melanoma
- Metastatic melanoma can present with a variety of symptoms, including lower extremity weakness, paresthesia, and pain 1, 2, 4.
- The spine is a common site for metastasis, and metastatic lesions can occur in the cervical, thoracic, or lumbar regions 2, 4, 5.
- Solitary metastases from melanoma to the skeleton and muscle are rare, and multimodality imaging including CT, MRI, and PET/CT can be useful in evaluating musculoskeletal findings 5.
- Histologic confirmation with a biopsy is recommended to diagnose a malignant solitary lesion, as image findings are not definitive 5.