The role of sentinel lymph node biopsy in the management of head and neck desmoplastic melanoma.

BACKGROUND: Desmoplastic melanoma (DM), a variant of spindle cell melanoma, has a higher propensity for local recurrence and a lower incidence of nodal metastasis. In this retrospective review, we evaluated the risk for regional nodal metastases and the need for sentinel lymph node biopsy (SLNB) in patients with head and neck DM. METHODS: We identified 103 patients with DM from an institutional database of patients with head and neck melanomas treated between 1985 and 2009. Forty-seven patients had their primary treatment at Memorial Sloan-Kettering Cancer Center, and 56 patients were treated for recurrent or metastatic disease. RESULTS: Of the 47 study patients, 27 were men and 20 were women with a median age of 71 years. All patients underwent wide excision, and 21 (44 %) underwent SLNB. None of the patients who underwent SLNB had positive nodes. The mean Breslow thickness for the 45 reported patients was 6.1 mm, with 84 % of tumors >2 mm in thickness and 55 % >4 mm. All known Clark thickness levels (n = 40) were IV or V. The overall survival was 73 %, with disease-specific survival of 84 %, local recurrence-free survival of 75 %, and neck recurrence-free survival of 97 % at 5 years. CONCLUSIONS: Although DM is diagnosed at higher Breslow thickness and Clark level, neck metastases are rare and prognosis is favorable compared to conventional melanoma. The low incidence of lymphovascular invasion, high frequency of histopathologically negative sentinel lymph nodes, and low neck recurrence rates indicate that staging of neck disease by SLNB is not necessary in patients with pure DM of the head and neck.