Sentinel lymph node biopsy in patients with “atypical Spitz tumors.” A report on 12 cases

Evaluation and Surgical Management of Pediatric Cutaneous Melanoma and Atypical Spitz and Non-Spitz Melanocytic Tumors (Melanocytomas): A Report From Children's Oncology Group

PURPOSE

The purpose of this study was to develop recommendations for the diagnostic evaluation and surgical management of cutaneous melanoma (CM) and atypical Spitz tumors (AST) and non-Spitz melanocytic tumors (melanocytomas) in pediatric (age 0-10 years) and adolescent (age 11-18 years) patients.

METHODS

A Children's Oncology Group-led panel with external, multidisciplinary CM specialists convened to develop recommendations on the basis of available data and expertise.

RESULTS

Thirty-three experts from multiple specialties (cutaneous/medical/surgical oncology, dermatology, and dermatopathology) established recommendations with supporting data from 87 peer-reviewed publications.

RECOMMENDATIONS

(1) Excisional biopsies with 1-3 mm margins should be performed when feasible for clinically suspicious melanocytic neoplasms. (2) Definitive surgical treatment for CM, including wide local excision and sentinel lymph node biopsy (SLNB), should follow National Comprehensive Cancer Network Guidelines in the absence of data from pediatric-specific surgery trials and/or cohort studies. (3) Accurate classification of ASTs as benign or malignant is more likely with immunohistochemistry and next-generation sequencing. (4) It may not be possible to classify some ASTs as likely/definitively benign or malignant after clinicopathologic and/or molecular correlation, and these Spitz tumors of uncertain malignant potential should be excised with 5 mm margins. (5) ASTs favored to be benign should be excised with 1- to 3-mm margins if transected on biopsy. (6) Re-excision is not necessary if the AST does not extend to the biopsy margin(s) when complete/excisional biopsy was performed. (7) SLNB should not be performed for Spitz tumors unless a diagnosis of CM is favored on clinicopathologic evaluation. (8) Non-Spitz melanocytomas have a presumed increased risk for progression to CM and should be excised with 1- to 3-mm margins if transected on biopsy. (9) Re-excision of non-Spitz melanocytomas is not necessary if the lesion is completely excised on biopsy.

Melanocytoma of the eyelid: Case report and introduction of new nomenclature

Purpose

The term melanocytoma was recently proposed for intermediate-stage melanocytic lesions with specific histopathologic and molecular genetic features. Prior studies have demonstrated a heightened potential for these intermediate lesions to spread to regional lymph nodes, with decreased likelihood for distant spread, when compared to melanomas.

Observations

Herein we present a case of a 28-year-old male who presented with a recurrent right lower eyelid margin combined cutaneous and palpebral conjunctival pigmented lesion, ultimately classified as a melanocytoma, to highlight this new nomenclature, characteristic histopathologic and genetic findings, and prognostic implications.

Conclusions

Ophthalmologists should be aware of this new cutaneous histopathologic classification system and apply to the periorbital region to improve melanocytic lesion management and surveillance.

Sentinel Lymph Node Biopsy in Atypical Spitz Tumor: A Systematic Review

BACKGROUND

Atypical Spitz tumor (AST) is an intermediate category among Spitz melanocytic neoplasms. Sentinel node biopsy (SNB) has been proposed in the clinical management of AST patients, but this approach remains the subject of debate. This systematic review aims to summarize the available evidence on SNB procedures in AST patients.

METHODS

A comprehensive search was conducted, including MEDLINE/Pubmed, EMBASE, and SCOPUS, through April 2023. Case series, cohort studies, and case-control studies of AST patients were eligible for inclusion. PRISMA guidelines were followed.

RESULTS

Twenty-two studies with a total of 756 AST patients were included. The pooled SNB prevalence was 54% (95% CI 32 to 75%), with substantial heterogeneity (I2 90%). The pooled SNB+ prevalence was 35% (95% CI 25 to 46%) with moderate heterogeneity (I2 39%). Lymphadenectomy was performed in 0-100% of SNB+ patients. Overall survival rates ranged from 93% to 100%, and disease-free survival ranged from 87% to 100% in AST patients. Overall and disease-free survival rates were 100% in SNB patients. Pooled survival estimates were not calculated due to the heterogeneous timing of the survival assessment and/or the small size of the subgroups. All studies clearly reported inclusion criteria and measured the condition in a standard way for all participants, but only 50% indicated valid methods for the identification of the condition.

CONCLUSIONS

The oncologic behavior of AST is related to an almost always favorable outcome. SNB does not seem to be relevant as a staging or prognostic procedure, and its indication remains debatable and controversial.

A Practical Approach to the Diagnosis of Melanocytic Lesions

CONTEXT.—

Melanocytic lesions are common in routine surgical pathology. Although the majority of these lesions can be confidently diagnosed using well-established morphologic criteria, there is a significant subset of lesions that can be diagnostically difficult. These can be a source of anxiety for patients, clinicians, and pathologists, and the potential consequences of a missed diagnosis of melanoma are serious.

OBJECTIVE.—

To provide a practical approach to the diagnosis of melanocytic lesions, including classic problem areas as well as suggestions for common challenges and appropriate incorporation of ancillary molecular techniques.

DATA SOURCES.—

Literature search using PubMed and Google Scholar, incorporating numerous search terms relevant to the particular section, combined with contemporaneous texts and lessons from personal experience.

CONCLUSIONS.—

Although a subset of melanocytic lesions can be diagnostically challenging, the combination of a methodical approach to histologic assessment, knowledge of potential diagnostic pitfalls, opinions from trusted colleagues, and judicious use of ancillary techniques can help the pathologist navigate this difficult area.

Metastases of malignant neoplasms: Historical, biological, & clinical considerations

The metastasis of neoplastic cells from their site of origin to distant anatomic locations continues to be the principal cause of death from malignant tumors, and that fact has been recognized by physicians for over a century. After the work done by Halsted in the treatment of breast cancer in the 1880s, accepted surgical canon held that metastasis occurred in a linear fashion, with centrifugal "growth in continuity" from the primary neoplasm that first involved regional lymph nodes. Those structures were considered to then be the sources of more distant, visceral metastases. With that premise in mind, radical and "ultra-radical" surgical procedures were devised to remove as many lymph nodes as possible in the treatment of carcinomas and melanomas. However, such interventions were ineffective in altering tumor-related mortality. This review considers the details of the historical material just mentioned. It also reviews currently-held concepts on biological mechanisms of metastasis, the "sentinel" lymph node biopsy technique, and the important topic of metastatic tumor "dormancy" as the cause of surgical treatment failure. Finally, predictive models of tumor behavior are discussed, which are based on gene signatures. These will likely be the key to identifying malignant lesions of low surgical stage that ultimately prove fatal through later manifestation of metastasis.

Sentinel lymph node biopsy is a prognostic measure in pediatric melanoma

BACKGROUND/PURPOSE

Sentinel lymph node biopsy (SLNB)-based management has been shown to improve disease-free survival in adult melanoma, but there is scant evidence regarding the utility of SLNB in pediatric melanoma.

METHODS

The 2004-2011 Surveillance, Epidemiology, and End Results database was queried for patients with primary cutaneous melanoma of Breslow depth>0.75mm and clinically negative nodes. Pediatric patients, defined as less than 20years of age, were grouped by whether they underwent SLNB or not. Kaplan-Meier analysis was performed to compare melanoma-specific survival (MSS) in propensity-matched groups.

RESULTS

310 pediatric patients met study criteria: 261 (84%) underwent SLNB, while 49 (16%) did not. There was no difference in MSS between matched children who received SLNB and those who did not (p=0.36). Among children who received SLNB, a positive SLNB was associated with worse MSS compared to a negative SLNB (89% vs. 100% at 84months, p=0.04). However, children with a positive SLNB had more favorable survival compared to patients >20years of age (88% vs. 66% at 84months, p=0.02).

CONCLUSIONS

SLNB does not confer a survival benefit to children with melanoma, but it provides valuable prognostic information regarding MSS.

Selected benign cutaneous lesions that may simulate melanoma histologically

As cutaneous melanomas manifest a wide spectrum of clinical and pathologic presentations, several other lesions enter into their differential diagnosis. This article considers those entities, including melanocytic hyperplasia, cellular nodules in congenital nevi, atypical lentiginous melanocytic proliferations, "special site" nevi, epithelioid histiocytoma, neurothekeoma, cellular schwannoma, and proliferating scars.

The complex management of atypical Spitz tumours

In recent years, advances in molecular genetic characterisation have revealed that atypical Spitz tumours (ASTs) are basically heterogeneous diseases, although the clinical relevance of these findings is yet to be determined. Evidence of molecularly-defined diverse groups of lesions continues to accumulate; however, conflicting, confusing, and overlapping terminology has fostered ambiguity and lack of clarity in the field in general. The lack of fundamental diagnostic (morphological) unambiguous classification framework results in a number of challenges in the interpretation of the molecular genetic data. In this review, we discuss the main difficulties for pathologists and clinicians in the complex management of ASTs, with particular emphasis on the different genetic and biological features of recently-described entities, and offer our view of what could be medically reasonable to guide a rational approach in light of current data.

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 Spitz tumors in patients younger than 18 years

BACKGROUND

Diagnosis and proper management of atypical Spitz tumors in pediatric age are still controversial.

OBJECTIVE

We sought to investigate the clinicopathological and molecular features of atypical Spitz tumors in patients aged 18 years or younger.

METHODS

We performed a retrospective clinicopathological and fluorescence in situ hybridization study on 50 pediatric atypical Spitz tumors.

RESULTS

Parameters that were significantly correlated with a diagnosis of atypical Spitz tumors over Spitz nevus included asymmetry, level IV/V, lack of maturation, solid growth, nuclear pleomorphism, high nuclear-cytoplasmic ratio, atypical and deep mitoses, and more than 6 mitoses/mm(2). In the atypical Spitz tumors group, a significantly higher mitotic rate was observed in prepuberal age (P = .04). The 4-probe fluorescence in situ hybridization melanoma assay did not discriminate atypical Spitz tumors from Spitz nevi. Heterozygous 9p21 loss was found in 3 of 37 cases and homozygous 9p21 loss in 2 of 37 cases. Only 1 child experienced a fatal outcome, showing genetic abnormalities by melanoma fluorescence in situ hybridization probe and a heterozygous 9p21 deletion.

LIMITATIONS

The limited number of adverse outcomes did not allow the prognostic analysis of single morphologic features.

CONCLUSION

Pediatric atypical Spitz tumors are associated with minimal lethal potential. Atypical Spitz tumors require complete excision and careful follow-up while our data do not support any clinical benefit for the sentinel lymph node biopsy procedure and completion lymphadenectomy.

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.

Junctional spitz tumor (nevus) of the upper lip

Spitz tumor (nevus) is a rare, melanocytic lesion that primarily affects children and adolescents. The lesion may share many clinical and histological similarities with malignant melanoma and careful microscopic examination is required to render the proper diagnosis. Complete excision with close follow-up is considered the appropriate treatment. Despite the common presentation of Spitz nevi on the facial skin, lip involvement has only rarely been described in the English language literature. In the present study, a case of Spitz tumor located on the vermilion border of the upper lip in a 16-year old female patient is reported.

[Melanoma in children: diagnosis and treatment specificities]

Skin melanoma is an extremely rare disease at pediatric age and its incidence increases with age. Links with predisposition syndrome exists (giant congenital naevus, xeroderma pigmentosum). Diagnosis is often difficult and distinction between benign or malignant lesion is sometime impossible (Spitzoid naevus, melanocytic neoplasms) leading to the diagnosis of "melanocytic tumor of uncertain malignant potential" (MELTUMP). Atypical features (amelanotic or raised lesions, atypical histotype) are frequent leading to delay in treatment. Diagnosis and treatment require expertise for pathologists and dermatologists pediatricians. Invasive melanomas are of poor prognosis despite recent progress in adult treatment. Early and rigorous treatment of suspect skin lesions is necessary.

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.

Outcomes in pediatric atypical spitz tumors treated without sentinel lymph node biopsy

The diagnosis of atypical Spitz tumor (AST) in a pediatric patient conveys an uncertain potential for malignancy. Although pediatric melanoma is rare, AST may be treated aggressively with sentinel lymph node biopsy (SLNB) and subsequent completion lymphadenectomy. These procedures have unclear therapeutic benefit and potential morbidity. We aimed to collect outcomes on children with AST treated with excision alone to assist in the management of these lesions. We queried our institution's pathology database for AST specimens submitted between 1994 and 2009. A dermatopathologist reviewed pathology slides to confirm AST diagnosis. Clinical information was obtained from medical records, and outcomes surveys were administered to children with AST. Twenty-nine patients met AST diagnostic criteria and were included in this study. Mean age at first excision was 9.0 ± 4.2 (range 2.3-17.5), and 19 patients underwent more than one excision procedure to achieve clear margins. No patient had SLNB. Fourteen patients (48%) with mean follow-up time of 8.4 years (range 3.5-15.8) completed clinical outcomes surveys. Outcomes with mean follow-up time of 2.8 years (range 0.02-8.1 years) were obtained for 10 additional patients from medical records. There were no reports of recurrence, additional lesions, or metastases in these 24 patients. We report one of the largest series of children with AST treated using excision alone and who remain disease free after a significant follow-up period. Our data suggest that SLNB is not warranted in the routine management of pediatric AST. We recommend complete excision with clear margins and careful clinical follow-up.

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.

An atypical melanocytic lesion without genomic abnormalities shows locoregional metastasis

A subset of difficult melanocytic lesions exists with histopathologic features that evade diagnostic consensus from even expert dermatopathologists. Comparative genomic hybridization (CGH) has emerged as a useful diagnostic tool to categorize these lesions, by identifying known chromosomal aberrations in malignant melanoma or the lack thereof in melanocytic nevi. However, determining a lesion's biological behavior primarily on CGH is limited by a relatively small series of corroborative cases without long term follow up. We present a case of a pigmented lesion on the right cheek of a 4 year old boy. The lesion had features of a deep penetrating nevus, but the presence of frequent mitoses, tumor infiltrating lymphocytes, and microscopic foci of tumor necrosis were concerning for an unusual melanoma. We termed this lesion a melanocytic tumor of uncertain potential (MELTUMP) for these reasons. High-resolution array-CGH performed elsewhere on the lesion demonstrated no melanoma-associated genomic abnormalities. A sentinel lymph node biopsy of this patient later revealed multiple small tumor deposits. Although the presence of nodal involvement in similar lesions often do not lead to progressive and fatal disease, this case illustrates that atypical melanocytic lesions with nodal involvement may not demonstrate genomic abnormalities by CGH, and that histopathologic assessment remains paramount in defining these difficult melanocytic lesions. Further comprehensive study of these lesions is needed.

An unconventional deep penetrating melanocytic nevus with microscopic involvement of regional lymph nodes

This manuscript represents a reprise of the preceding manuscript (J Cutan Pathol 2012; 39: 21-24). It has different conclusions. The wording of the case report section is very similar in both papers but has been included in both for the convenience of the reader. The illustrations are duplicated in both versions of the manuscript but the captions are not the same. The reader is encouraged to study both versions of the manuscript and consider the issue from both perspectives.

Spitz nevi and other Spitzoid lesions part II. Natural history and management

For dermatologists, evidence-based management guidelines for Spitz tumors have not been established. Despite the lack of a standardized approach, most dermatologists recommend the excision of Spitz tumors occurring in adults and adopt more conservative measures towards pediatric cases. The histopathologic attributes and the clinical scenario are factored into management in each case. While the metastatic behavior of certain Spitz tumors is well known, the malignant potential of these lesions remains unclear because they only rarely result in negative outcomes. The risks and benefits of adjunctive measures, such as sentinel lymph node biopsy and interferon use, remain untested and are subjects of ongoing controversy. (In part II of this continuing medical education article, we will continue to use the terminology defined in part I for purposes of continuity. "Spitz tumor" is used as the umbrella term for the entire category of lesions, "common Spitz nevi" refers to only the most typical lesions seen in pediatric cases, and "atypical Spitz tumors" encompass the "all other" category, which continues to cause debate.).

Atypical spitzoid melanocytic neoplasms with angiotropism: a potential mechanism of locoregional involvement

Atypical spitzoid melanocytic neoplasms (ASMN) may prove difficult to distinguish microscopically from melanoma, and their biological behavior may be unpredictable. ASMN may result in regional lymph node (LN) metastases and frequent sentinel lymph node (SLN) deposits. Angiotropism and extravascular migratory metastasis may account for locoregional metastases in melanoma and thus may potentially explain such locoregional involvement in ASMN. Nine ASMN with angiotropism from 2006 to 2010 were studied. Angiotropism was defined as melanocytes closely opposed to the external surfaces of microvascular channels without intravasation. There were 5 women and 4 men aged 6-40 (mean 18.7) years with ASMN involving the head and neck (5), the extremities (3), and the trunk (1), and the lesions ranged in diameters from 3.5 to 10 (mean 6.2) mm. Breslow thicknesses ranged from 0.66 to 5.35 (mean 3.21) mm, 5 lesions Clark level IV and 4 level V, and dermal mitotic rates varied from 1 to 5 (mean 2.4) per square millimeter. Despite follow-up of 6 months or less in 4 subjects, 5 patients showed regional tumor spread based on detection of SLN deposits, local recurrence, or clinical satellite and LN metastases. Four of 5 patients (80%) undergoing SLN biopsy showed nodal positivity with 2 SLN deposits of >6 mm. Among 4 patients not having SLN biopsy, 1 patient developed local LN metastases after 2 years. We report for the first time angiotropism in ASMN and suggest that such angiotropism seems to correlate with and may explain regional tumor spread in this neoplastic system.

Atypical Spitzoid melanocytic tumors: a morphological, mutational, and FISH analysis

BACKGROUND

Identification of the clinical behavior of atypical Spitzoid tumors with conflicting histopathologic features remains controversial.

OBJECTIVE

We sought to assess whether molecular findings may be helpful in the diagnostic and prognostic assessment of atypical Spitzoid tumors.

METHODS

A total of 38 controversial, atypical Spitzoid lesions (≥ 1 mm in thickness) were analyzed for clinicopathological features, chromosomal alterations by fluorescence in situ hybridization (FISH) analysis (RREB1/MYB/CCND1/CEP6), BRAF(V600E) mutation by allele-specific real-time polymerase chain reaction confirmed by sequencing, and H-RAS gene mutation by direct sequencing.

RESULTS

Atypical Spitzoid lesions developed in 21 female and 17 male patients (mean age 22 years). Nine patients underwent sentinel lymph node biopsy and a sentinel lymph node micrometastasis was detected in 4 of these 9 cases. Four additional patients, who did not receive a sentinel lymph node biopsy, experienced bulky lymph node metastases and one experienced visceral metastases and death. Lesions from patients with lymph node involvement showed more deep mitoses (P < .01), less inflammation (P = .05), and more plasma cells (P = .04). FISH analysis demonstrated the presence of chromosomal alterations in 6 of 25 cases. Correlation with follow-up data showed that the only case with fatal outcome showed multiple chromosomal alterations by FISH analysis. BRAF(V600E) mutation was detected in 12 of 16 cases (75%) and H-RAS mutation on exon 3 was found in 3 of 11 cases (27%).

LIMITATIONS

Our results require validation in a larger series with longer follow-up information.

CONCLUSIONS

FISH assay may be of help in the prognostic evaluation of atypical Spitzoid tumors. Diagnostic significance of BRAF(V600E) and H-RAS mutations in this setting remains unclear.

Long-term outcome of Spitz-type melanocytic tumors

OBJECTIVE

Despite recent advances in our molecular understanding of Spitz-type tumors, the clinical behavior of these lesions remains unclear. We thus set out to define the clinical outcome of classic Spitz nevi, atypical Spitz tumors (ASTs), and spitzoid melanomas.

DESIGN

From 1987 through 2002, data on all lesions containing the term "Spitz" or "Spitz" [AND] "melanoma" were retrieved from the pathology database at Massachusetts General Hospital, and the cases were followed up for their outcome.

SETTING

The study was performed at a university-affiliated tertiary health care center in Boston, Massachusetts.

PATIENTS

A total of 157 patients with Spitz-type melanocytic lesions and follow-up information were identified.

MAIN OUTCOME MEASURES

Sentinel lymph node biopsy results, metastases, or fatality were assessed.

RESULTS

There were 68 classic Spitz nevi, 76 ASTs, 10 spitzoid melanomas, and 3 melanomas that arose in Spitz nevi. Spitz nevi were diagnosed at a younger age than ASTs (mean age, 26.4 years vs 33.7 years) (P = .01), though both occurred earlier than melanomas (mean age, 50.4 years, P < .001). Sentinel lymph node biopsy findings were positive in 1 of 6 and 4 of 8 patients with ASTs and spitzoid melanomas, respectively. After a median follow-up of 9.1 years, only 1 patient with an AST, who had a separate intermediate-thickness melanoma, developed distant metastasis. There were 6 documented invasive melanomas among 144 patients with classic Spitz nevi or ASTs (observed/expected ratio, 8.03) (P = .01).

CONCLUSIONS

Atypical Spitz tumors are associated with minimal lethal potential, an increased melanoma risk, and a moderate risk of metastasis to regional nodes. It makes clinical sense to minimize aggressive treatment but to offer careful surveillance for rare relapses and subsequent melanomas.

Nevus/Melanocytoma/Melanoma: an emerging paradigm for classification of melanocytic neoplasms?

CONTEXT

Until recently, the prevailing paradigm in classification and clinical management of melanocytic proliferations mandated dichotomous classification of all melanocytic lesions as either entirely benign (nevus) or entirely malignant (melanoma). However, some diagnostically challenging lesions cannot be unequivocally classified as nevus or melanoma by histologic evaluation of the primary tumor. Such lesions have been referred to as borderline or melanocytic tumors of uncertain malignant potential.

OBJECTIVE

To review and update the problem of diagnostically difficult melanocytic proliferations and recent concepts regarding borderline melanocytic tumors.

DATA SOURCES

Published literature and personal experience of the authors.

CONCLUSIONS

Preliminary evidence indicates that it may be appropriate to expand the classification scheme of melanocytic neoplasms to include a third diagnostic category of melanocytic lesions of intermediate malignant potential that are capable of metastasis to regional lymph nodes but have limited potential for distant spread. We propose the term melanocytoma for this group of lesions. We believe that a nevus/melanocytoma/melanoma paradigm may provide a useful intellectual framework to understand, research, and clinically manage borderline melanocytic tumors.

Melanoma in children

CONTEXT

Cutaneous melanoma in childhood (CMC) is rare; therefore, its prognostic factors and biologic behavior, and the effectiveness of adjuvant techniques for CMC remain mostly unknown.

OBJECTIVE

To review the most useful, evidence-based practice criteria for establishing the diagnosis of CMC, for which universally accepted criteria are lacking, in order to facilitate the interpretation and comparison of the results from different institutions, and to perform systematic reviews and meta-analysis.

DATA SOURCES

A comprehensive review of the most relevant previous single-institution series reported in the literature since 1990, including our cumulative experience of 137 cases of primary cutaneous and mucosal melanoma in patients younger than 18 years. Special characteristics of melanoma in children are discussed, regarding clinical settings and risk factors, helpful histologic features, and immunohistochemical patterns for diagnosis and prognosis.

CONCLUSIONS

Careful analysis of histologic features as well as the additional information provided by immunohistochemistry should allow for a correct diagnosis in most cases of melanoma in children. Although it seems that pediatric patients with melanoma have higher survival probability than adults, still a number of children will develop metastasis and die of their disease, particularly when melanoma is diagnosed after puberty. Until further studies more accurately determine the prognosis, a prudent approach to CMC diagnosis and therapy seems to follow the same principles as those established for adult melanoma.

Histologically ambiguous ("borderline") primary cutaneous melanocytic tumors: approaches to patient management including the roles of molecular testing and sentinel lymph node biopsy

It is well recognized that the pathologic diagnosis of melanocytic tumors can sometimes be difficult. For some atypical melanocytic tumors that do not display clear-cut features of malignancy, it may be difficult or impossible to exclude a diagnosis of melanoma; this includes those showing some resemblance to Spitz nevi, blue nevi, deep penetrating nevi, and possible nevoid melanomas. When there is uncertainty about whether a primary melanocytic tumor is a nevus or a melanoma, we recommend that a second opinion be sought from one or more experienced colleagues. If diagnostic uncertainty persists, the evidence for or against the various differential diagnostic considerations should be presented in the pathology report and a "most likely" or "favored" diagnosis given. Molecular testing of the primary tumor by using techniques such as comparative genomic hybridization or fluorescence in situ hybridization may assist in establishing a diagnosis of melanoma if multiple chromosomal aberrations are identified. However, these tests require further independent validation and are not widely available at present. Complete excision of the lesion is probably mandatory, but plans for further management should be formulated on a case-by-case basis. While the safest course of action will usually be to manage the tumor as if it were a melanoma (taking into account the tumor's thickness and other prognostic variables), this may not always be appropriate, particularly if it is located in a cosmetically sensitive site such as the face. In some cases, it may be appropriate for the surgical oncologist to convey the diagnostic uncertainty to patients and to present them with management choices so that they can decide whether they wish to be managed aggressively (as for a melanoma) or conservatively. While a sentinel lymph node biopsy may be recommended on the basis of the primary tumor characteristics, the clinical significance of lymph node involvement for these tumors is not yet clear, and it may not have the same prognostic implications as nodal involvement from an unequivocal "conventional" melanoma.

Spindle cell melanocytic lesions--part I: an approach to compound naevoidal pattern lesions with spindle cell morphology and Spitzoid pattern lesions

Melanocytic lesions show great morphological diversity in their architecture and the cytomorphological appearance of their composite cells. Whereas functional melanocytes reveal a dendritic cytomorphology and territorial isolation, lesional naevomelanocytes and melanoma cells typically show epithelioid, spindled or mixed cytomorphologies and a range of architectural arrangements. Spindling is common to melanocytic lesions, and may be either a characteristic feature or a divergent appearance. The presence of spindle cells may mask the melanocytic nature of a lesion, and is often disconcerting, either because of its infrequent appearance in a particular lesion or its interpretation as a dedifferentiated phenotype. Spindle cell melanocytic lesions follow the full spectrum of potential biological outcomes, and difficulty may be experienced judging the nature of a lesion because of a lack of consistently reliable features to predict biological behaviour. Over time, recognition of numerous histomorphological features that may portend a more aggressive lesion have been identified. However, the translation of these features into a diagnostic entity requires a gestalt approach. Although most spindle cell melanocytic lesions can reliably be resolved with this standard approach, problem areas do exist and cause no end of grief to the surgical pathologist or dermatopathologist. In this review, the authors present their algorithmic approach to spindle cell melanocytic lesions and discuss each entity in turn, in order to (1) model a systematic approach to such lesions, and (2) provide familiarity with those melanocytic lesions that either typically or occasionally display a spindled cytomorphology.

The role of lymphatic mapping and sentinel node biopsy in the management of atypical and anomalous melanocytic lesions

Atypical and anomalous melanocytic lesions are tumors that cannot be determined by microscopy to be certainly benign or fully malignant. The malignant potential of these borderline lesions is unknown and logical determination of best therapy is challenging, in particular whether lymphatic mapping and sentinel node biopsy have a place in their management. Lesions that fall into this category include atypical Spitzoid lesions, atypical cellular blue nevi, combined nevi, deep penetrating nevi, ancient nevi, desmoplastic nevi, balloon cell nevi and proliferation nodules of congenital nevi. We report our experience managing patients with these problematic tumors and discuss our approaches to determining the true location of lesional cells in sentinel nodes.

Melanoma and melanocytic tumors of uncertain malignant potential in children, adolescents and young adults--the Stanford experience 1995-2008

Pediatric melanoma is difficult to study because of its rarity, possible biological differences in preadolescents compared with adolescents, and challenges of differentiating true melanoma from atypical spitzoid neoplasms. Indeterminant lesions are sometimes designated as melanocytic tumors of uncertain malignant potential (MelTUMPs). We performed a retrospective, single-institution review of melanomas, MelTUMPs and Spitz nevi with atypical features (SNAFs) in patients at 21 years of age and younger from 1995 to 2008. We identified 13 patients with melanoma, seven with MelTUMPs, and five with SNAFs. The median age for melanoma patients was 17 years, 10 for MelTUMPs, and six for SNAFs. Of the 13 melanoma patients, only four were younger than 15 years, while six were adolescents, and three were young adults. Nine melanoma patients (69%) were female. The most common histologic subtype was superficial spreading. The median depth for melanomas was 1.2 mm, and 3.4 mm for MelTUMPs. Microscopic regional nodal involvement detected on elective or sentinel lymph node (SLN) dissection was present in 2/10 (20%) of primary melanomas and 2/6 (33%) of Mel-TUMPs. Complete lymphadenectomy was performed on four melanoma patients, with three positive cases. Patient outcome through March 31, 2009 revealed no in-transit or visceral metastasis in patients with MelTUMPs or SNAFs. One SLN-positive patient (8%) with melanoma developed recurrent lymph node and liver metastasis and died 15 months after primary diagnosis. Our data highlight the rarity, female predominance, and significant rate of SLN positivity of pediatric melanoma. The high rate of MelTUMPs with regional nodal disease reinforces the need for close follow-up.

Utility of lymph node assessment for atypical spitzoid melanocytic neoplasms

BACKGROUND

Atypical spitzoid melanocytic neoplasms (ASMN) are cutaneous lesions of uncertain malignant potential, which can be difficult to distinguish from cutaneous melanoma. Sentinel lymph node (SLN) biopsy is a safe and useful prognostic tool for staging melanoma, but its role in staging ASMNs is not established nor is the significance of positive SLNs in these patients known. This study attempts to characterize the significance of nodal disease in ASMN.

METHODS

Patients with ASMNs who presented to the melanoma service from 1992 to 2007 were identified from a prospective database. Histological review was performed by two dermatopathologists. Demographic, treatment, and outcome data were reviewed.

RESULTS

A total of 58 patients with ASMNs were treated during the time analyzed; 31 (53%) underwent wide local excision and observation (WLE); 27 underwent wide excision and SLN biopsy. Median age was 24 (range, 6-60) years. Mean Breslow thickness was 2.9 (range, 0.5-10) mm. Median follow-up was 56 (range, 1-160) months. Ten of 58 (17%) patients had nodal metastasis. Four (13%) of 31 patients who underwent WLE developed nodal recurrences, and 6 of 27 (22%) patients had a positive SLN biopsy. Of patients with positive SLNs, none have recurred after undergoing completion lymphadenectomy. One patient presented with synchronous brain metastasis and inguinal lymphadenopathy and died of disease.

CONCLUSIONS

Nodal status does not seem to convey the same prognosis that it does in standard melanoma. There may be a limited ability for progression within the nodal basin in patients with these lesions. This subset of patients would benefit from genetic data complementing histologic analysis.

Pigmented lesion pathology: what you should expect from your pathologist, and what your pathologist should expect from you

The first part of this review examines the reliability of histologic diagnosis in pigmented lesions, as measured by concordance studies and medicolegal analysis. It emphasizes the role of clinicians in maximizing that reliability, by providing adequate clinical descriptions, using appropriate biopsy technique, and critically interpreting pathology reports. It identifies those entities that are especially problematic, either because they cannot be reliably recognized by the histopathologist or because their histology is a poor guide to their biologic behavior. The second part of the review is a guide to some of the more difficult and controversial pigmented lesions, including dysplastic nevus, spitzoid nevi and melanomas, cellular blue nevus, animal-type melanoma, and deep penetrating nevus.