Non-sentinel lymph node involvement in a patient with an atypical Spitz tumor and a positive sentinel node. Report of a case and review of the literature

Pediatric Melanoma and Atypical Melanocytic Neoplasms

Melanoma is uncommon in the pediatric age range, but is increasing in frequency and often presents with atypical features compared to the classic ABCDE criteria common to adult melanoma cases. Moreover, many melanocytic neoplasms in childhood pose diagnostic challenges to the pathologist, and sometimes cannot be unequivocally classified as benign nevi or melanoma. This chapter addresses the evaluation and management of pediatric patients with melanoma and atypical melanocytic neoplasms, including the roles of and unresolved questions surrounding sentinel lymph node biopsy, completion lymphadenectomy, adjuvant therapy, and treatment of advanced disease.

Atypical Spitzoid neoplasms: a review of potential markers of biological behavior including sentinel node biopsy

Atypical cutaneous melanocytic lesions, including those with Spitzoid features, can be difficult to categorize as benign or malignant. This can lead to suboptimal management, with potential adverse patient outcomes. Recent studies have enhanced knowledge of the molecular and genetic biology of these lesions and, combined with clinicopathological findings, is further defining their biological spectrum, classification, and behavior. Sentinel node biopsy provides important prognostic information in patients with cutaneous melanoma, but its role in the management of melanocytic lesions of uncertain malignant potential (MELTUMP) is controversial. This paper examines the role of molecular testing and sentinel node biopsy in MELTUMPs, particularly atypical Spitzoid tumors.

Atypical Spitz tumours and sentinel lymph node biopsy: a systematic review

Sentinel lymph node biopsy has been proposed as a diagnostic method for estimation of the malignant potential of atypical Spitz tumours. However, although cell deposits are commonly detected in the sentinel lymph nodes of patients with atypical Spitz tumours, their prognosis is substantially better than that of patients with melanoma and positive sentinel lymph node biopsies. We did a systematic review of published reports to assess the role of sentinel lymph node biopsy as a prognostic method in the management of atypical Spitz tumours. The results of our analysis did not show any prognostic benefit of sentinel lymph node biopsy; having a positive sentinel lymph node does not seem to predict a poorer outcome for patients with atypical Spitz tumours. These findings indicate that, especially in the paediatric population, it might be prudent initially to use complete excision with clear margins and careful clinical follow-up in patients with atypical Spitz tumours.

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

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.

Sentinel node biopsy in atypical melanocytic neoplasms in childhood: a single institution experience in 24 patients

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is a controversial but frequently used adjunct to wide excision of difficult-to-diagnose melanocytic proliferations of childhood. We herein report our institutional experience with SLNB in pediatric patients with these lesions, hereafter referred to as 'atypical melanocytic proliferations'.

METHODS

Our prospectively collected melanoma database was queried for patients ≤21 years of age status post-SLNB for a diagnosis of atypical melanocytic proliferation in which the diagnosis of melanoma ≥1 mm in depth was considered in the differential diagnosis by one or more expert dermatopathologists and for which no diagnostic consensus could be reached.

RESULTS

Of 24 patients identified over 17 years, 7 patients (29%) had a positive sentinel lymph node (SLN). Six SLN-positive patients underwent complete lymph node dissection, with one (14%) having additional nodal involvement identified. With a median follow-up of 4.1 years (range < 0.1 to 14.8 years), all patients showed no evidence of disease.

CONCLUSIONS

Despite a significant rate of identification of melanocytes in SLNs of children with atypical melanocytic proliferations, survival appears favorable and controversy surrounding the significance of nodal involvement remains. Further studies with larger numbers of patients and long-term follow-up are needed before the true prognostic value of SLNB in this setting can be determined.