Navigation-assisted localisation and resection of subclinical metastatic malignant melanoma of unknown primary based on 18-fluorodeoxyglcose positron emission tomography computed tomography fusion imaging

PET-CT images showing FDG-avid lesions in the temporal area (red arrows) and the level 5 neck (yellow arrows).

Using segmentation, the area of enhanced radiotracer activity was isolated (marked area behind the ear).

Using the instrument pointer, the target area was identified purely by stereotactic navigation and was marked out with surgical marking ink. Note the three passive markers fixed on the contralateral skull.

Resection material. The specimen measured 36mm across and was 11mm deep. At a depth of 6mm, in the subcutaneous and fat layers, a small lymph node with a maximum diameter of 12mm was found. It was completely replaced by metastatic malignant melanoma. This lymph node was situated towards the anterior aspect of the specimen, approximately 7mm from the anterior margin, 4mm from the superior margin and 3mm from the deep margin.