Objective: Establishing the frequency of nodal naevi in lymph-node dissections from patients with a melanoma who have undergone a sentinel-node procedure and/or regional node dissection and distinguishing naevi from melanoma metastases.
Design: Retrospective and descriptive.
Methods: Patients with a nodal naevus in the sentinel node were selected from a database containing clinical and pathological data on all 65 patients who underwent a sentinel-node procedure for melanoma at our hospital between 1998 and 2001. Also data from the pathology department on the case frequency and the nodal frequency of nodal naevi in the total number of patients with melanoma in whom a sentinel-node procedure and/or therapeutic node dissection had been carried out during the same period, were examined.
Results: In 5 patients a nodal naevus was found in the sentinel node. The case frequency was 6.2% and the nodal frequency 0.65%. Distinction from melanoma metastases was made by the use of H&E colouring, localization, architectural and morphological features of the melanocyte cell clusters in the lymph node and sometimes after consultation with the National Melanoma Panel. Immunohistochemical markers provided supplementary information only.
Conclusion: Nodal naevi in lymph nodes were not uncommon in people with melanoma and can be distinguished from the micrometastases from melanoma.