[497] Atypical Spitz Neoplasm: Indolent Clinical Behavior and No Role for Sentinel Lymph Node Biopsy in Predicting Outcome

Alireza Sepehr, Farhad Islami. Beth Israel Deaconess Medical Center & Harvard Medical School, Boston, MA; Mount Sinai School of Medicine, New York, NY

Background: Atypical Spitz neoplasms (ASN) are rare melanocytic tumors and have been the subject of several studies due to difficulties in their histopathologic classification, unknown biologic behavior and challenges in the management. Most studies are limited because of small sample size and/or short follow up period. We performed a meta analysis on ASNs and combined results of every study published as of to date to assess any association between clinical and histopathologic parameters with their behavior, and to evaluate the role of sentinel lymph node biopsy (SLNB) in predicting clinical outcome.
Design: A total of 251 studies were identified. Cases of Spitzoid neoplasm harboring unequivocal benign or malignant diagnoses and duplicate cases were excluded. Predictors of behavior including age, sex, Breslow depth, mitotic figures, status of the surgical margin, SLNB, completion lymphadenectomy, other treatments and follow up length were documented for each case. Measured outcomes included disease free status, recurrence, and stage IV disease/death.
Results: From 1989 to 2012, 38 studies were included with a total of 551 patients; 545 (98.9%) patients were alive at last follow up (mean 59.3 months), and 96.7% were disease-free at last follow up. In 3 patients who died of the disease, Breslow thickness was higher (5.0 mm; SD 3.4) compared to 293 patients who were alive (3.1 mm; SD 2.1), but this difference was not significant. Mitoses also failed to predict the outcome of ASN. SLNB was positive in 110/281 patients (39.1%) and 2 patients with positive SLNB died of the disease. Among those who were alive/disease-free at the end of follow up, 40% had a positive SLNB. There was no significant difference in having positive SLNB between those who were alive and those who had died, and between disease-free patients and those with disease at last follow up.
Conclusions: After a meta analysis on all reported cases of ASN (n=551), predictors of tumor behavior such as Breslow depth, mitotic figures, and SLNB failed to predict the outcome. Due to low prevalence of ASN, very rare poor outcomes, and relatively short follow up, detection of any clinically significant difference is challenging; however, the data suggest ASN has an indolent course. In the absence of compelling evidence on the value of therapeutic interventions in predicting the outcome, usefulness of procedures such as SLNB should be revisited.
Category: Dermatopathology

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 44, Tuesday Morning


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