Utility of lymph node assessment for atypical spitzoid melanocytic neoplasms

Atypical spitzoid melanocytic neoplasms (ASMN) are cutaneous lesions of uncertain malignant potential, which can be difficult to distinguish from cutaneous melanoma. Sentinel lymph node (SLN) biopsy is a safe and useful prognostic tool for staging melanoma, but its role in staging ASMNs is not established nor is the significance of positive SLNs in these patients known. This study attempts to characterize the significance of nodal disease in ASMN.

Patients with ASMNs who presented to the melanoma service from 1992 to 2007 were identified from a prospective database. Histological review was performed by two dermatopathologists. Demographic, treatment, and outcome data were reviewed.

A total of 58 patients with ASMNs were treated during the time analyzed; 31 (53%) underwent wide local excision and observation (WLE); 27 underwent wide excision and SLN biopsy. Median age was 24 (range, 6-60) years. Mean Breslow thickness was 2.9 (range, 0.5-10) mm. Median follow-up was 56 (range, 1-160) months. Ten of 58 (17%) patients had nodal metastasis. Four (13%) of 31 patients who underwent WLE developed nodal recurrences, and 6 of 27 (22%) patients had a positive SLN biopsy. Of patients with positive SLNs, none have recurred after undergoing completion lymphadenectomy. One patient presented with synchronous brain metastasis and inguinal lymphadenopathy and died of disease.

Nodal status does not seem to convey the same prognosis that it does in standard melanoma. There may be a limited ability for progression within the nodal basin in patients with these lesions. This subset of patients would benefit from genetic data complementing histologic analysis.