[505] Sentinel Lymph Node Metastases in Problematic Spitzoid Melanocytic Tumors: Not a Predictor of Malignancy

Tawny Hung, Adriano Piris, Alice Lobo, Martin M Mihm, Arthur J Sober, Hensin Tsao, Kenneth K Tanabe, Lyn McDivitt Duncan. Vancouver General Hospital and University of British Columbia, Vancouver, BC, Canada; Massachusetts General Hospital and Harvard Medical School, Boston, MA; Hospital das Clinicas, University of Sao Paulo, Sao Paulo, Brazil; Brigham and Women's Hospital and Harvard Medical School, Boston, MA

Background: The diagnosis and classification of spitzoid melanocytic tumors with atypical features remains problematic and controversial. Previously, sentinel lymph node mapping was advocated as a diagnostic test in this setting to potentially discriminate melanoma from benign tumors. Recent studies suggest that despite the presence of lymph node metastases, these patients almost always fare well. Here, we examined the outcome of patients with atypical Spitz tumors and spitzoid melanoma who received sentinel lymph node mapping, combined these findings with others' data and clarified the current state of the art in managing patients with these diagnostically challenging tumors.
Design: A search of the electronic files of the MGH Pathology Service identified forty-one patients treated with sentinel lymph node biopsy for atypical Spitz tumor or spitzoid melanoma from 1998-2008. These patients included 23 patients with atypical Spitz tumors and 18 patients with spitzoid melanoma. The following were recorded for each case: age, gender, location, status of the sentinel lymph node biopsy, status of the complete therapeutic lymph node dissection, treatment with interferon-alpha, duration of clinical follow up, recurrence or metastatsis beyond the regional lymph node basin, and death from metastatic disease.
Results: Sentinel lymph nodes were positive in 26% of atypical Spitz tumors (6/23) and 33% of spitzoid melanomas (6/18). One patient with Spitzoid melanoma developed in transit metastasis; none of the 41 patients developed metastases beyond the regional lymph node basin with a median follow up of 55 months. Follow up exceeded 4 years in 26 of 41.
Conclusions: SLN biopsy does not appear helpful as a discriminatory test or have a therapeutic benefit in patients with atypical Spitz tumors. Patients with spitzoid melanomas also appear to have a more indolent course than would be predicted by the presence of positive sentinel lymph nodes.
Category: Dermatopathology

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 100, Wednesday Afternoon


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