Sentinel lymph node metastasis is not predictive of poor outcome in patients with problematic spitzoid melanocytic tumors

Abstract

The diagnosis and clinical management of spitzoid melanocytic tumors with atypical features remain problematic and controversial. In the past decade, sentinel lymph node mapping has been advocated as a diagnostic test in this setting to discriminate melanoma from benign tumors. Recent studies, however, consistently show that despite the presence of lymph node metastases these patients almost always fare well. We investigated the outcome of patients with atypical Spitz tumors and spitzoid melanoma who received sentinel lymph node mapping to clarify current recommendations in managing patients with these diagnostically challenging tumors. A search of the electronic files of the Massachusetts General Hospital Pathology Service identified 41 patients treated with sentinel lymph node biopsy for atypical Spitz tumor or spitzoid melanoma from 1998 to 2008. These patients included 23 patients with atypical Spitz tumors and 17 patients with spitzoid melanoma. Sentinel lymph nodes were positive in 26% of patients with atypical Spitz tumors (6/23) and 35% with spitzoid melanomas (6/17). One patient with spitzoid melanoma developed in-transit metastasis; 0 of 40 patients developed metastases beyond the regional lymph node basin with a mean follow-up of 57 months. Sentinel lymph node biopsy may not be a reliable prognostic discriminatory test in patients with atypical Spitz tumors. Patients with spitzoid melanomas and positive sentinel lymph nodes have a more indolent course than those with bona fide conventional melanoma and positive sentinel nodes.