Sentinel lymph node biopsy for atypical melanocytic lesions with spitzoid features

Sentinel lymph node biopsy (SLNB) is routinely used as a staging procedure for melanomas, however may also assist in understanding the biology of atypical and controversial spitzoid melanocytic skin lesions.

Five hundred and forty-nine sentinal lymph node excisions were performed over a 5-year period. Fourteen patients with controversial melanocytic lesions were identified and of these ten underwent SLNB. The histology of the primary skin lesion and corresponding sentinal lymph nodes were evaluated and correlated with outcome.

Thickness of the primary melanocytic lesion ranged from 1.22 to 4 mm. Fifty percent of patients were less than 17 years of age. Ten patients underwent SLNB and three cases (30%) displayed metastatic disease in the SLNB specimen. All three patients were under 17 years of age and all underwent completion axillary dissection. One completion axillary dissection had an additional node with metastasis on routine H&E and immunohistochemical staining. No capsular invasion was seen. All three cases with metastatic disease received adjuvant systemic therapy and remain disease free at 29, 49 and 57 months follow-up. All patients with a negative SLNB remain disease free at mean follow-up of 28.1 months (range: 13-40 months).

Our results confirm that some of these spitzoid lesions metastasize to regional lymph nodes and SLNB is a valuable adjunct tool in staging these lesions. However, molecular studies and a prolonged follow-up are needed to determine whether these lesions, especially those occurring in children are comparable to stage matched overt melanoma in adults.