Staging of cutaneous melanoma

Abstract

The American Joint Committee on Cancer (AJCC) staging of cutaneous melanoma is a continuously evolving system. The identification of increasingly more accurate prognostic factors has led to major changes in melanoma staging over the years, and the current system described in this review will likely be modified in the near future. Likewise, application of new imaging techniques has also changed the staging work-up of patients with cutaneous melanoma. Chest and abdominal computed tomography (CT) scanning is most commonly used for evaluation of potential metastatic sites in the lungs, lymph nodes and liver, and is indicated in patients with new symptoms, anaemia, elevated lactate dehydrogenase or a chest X-ray abnormality. CT scans should be restricted to patients with high-risk melanoma (stage IIC, IIIB, IIIC and stage IIIA with a macroscopic sentinel lymph node). Magnetic resonance imaging (MRI) of the brain is a mandatory test in patients with stage IV, optional in stage III and not used in patients with stage I and II disease. Positron emission tomography (PET)/CT is more accurate than CT or MRI alone in the diagnosis of metastases and should complement conventional CT/MRI imaging in the staging work-up of patients who have solitary or oligometastatic disease where surgical resection is most relevant.

Figure 1.

Ultrasound image of a metastatic lymph node. The lesion reveals the typical appearance of a lymph node metastasis during follow-up showing a balloon shape, and irregular and mostly peripherally located hyper-perfusion corresponding to neo-angiogenesis. The suspicious lymph node can easily be evaluated with FNAC.

Figure 2.

Ultrasound of a benign lymph node. Both oval-shaped lesions show an enlarged but normal reactive lymph node with central echoes in B-mode and peripheral lack of echoes according to the parenchyma and centrally located perfusion. These lesions can safely be validated by ultrasound alone.