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

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.

Melanoma in children: A systematic review and individual patient meta-analysis

The current evidence on paediatric melanoma is heterogeneous, especially regarding the prognosis of different histological subtypes. We sought to systematically review the evidence on paediatric melanoma, highlighting the major sources of heterogeneity and focusing on available data on single patients. A systematic search was performed from 1948 to 25 January 2021. Only studies reporting at least one case of cutaneous melanoma in patients aged ≤18 years were included. Unknown primary and uncertain malignant melanomas were excluded. Three couples of authors independently performed title/abstract screening and two different authors reviewed all the relevant full texts. The selected articles were manually cross-checked for overlapping data for qualitative synthesis. Subsequently data on single patients were extracted to perform a patient-level meta-analysis. PROSPERO registration number: CRD42021233248. The main outcomes were melanoma-specific survival (MSS) and progression-free survival (PFS) outcomes. Separate analyses were done of cases with complete information on histologic subtype, focusing on superficial spreading (SSM), nodular (NM) and spitzoid melanomas, as well as of those classified as de-novo (DNM) and acquired or congenital nevus-associated melanomas (NAM). The qualitative synthesis covered 266 studies; however, data on single patients were available from 213 studies including 1002 patients. Among histologic subtypes, NM had a lower MSS than both SSM and spitzoid melanoma, and a lower PFS than SSM. Spitzoid melanoma had a significantly higher progression risk than SSM and trended toward lower mortality. Focusing on nevus-associated status, DNM demonstrated better MSS after progression than congenital NAM, and no differences were highlighted in PFS. Our findings describe the existence of different biological patterns in paediatric melanoma. Specifically, spitzoid melanomas demonstrated intermediate behaviour between SSM and NM and showed a high risk of nodal progression but low mortality. This raises the question of whether spitzoid lesions are being over-diagnosed as melanoma in childhood.

Interpretation of the Complex Melanoma Pathology Report

An ambiguous pathologic report can present a clinical dilemma to the treating surgeon. We describe lesions ranging from the potentially benign to the likely malignant. Correctly identifying features associated with higher-risk lesions has proven challenging given the overall good prognosis and low rate of events. An appropriate treatment plan generally requires discussion between the surgeon and an experienced dermatopathologist. When clinically indicated, additional testing may be used to further support or refute a diagnosis of melanoma. The indications for these techniques, the data to support their use, and the strengths and weakness of each are reviewed.

Atypical Melanocytic Proliferations: A Review of the Literature

BACKGROUND

Ambiguous histopathologic diagnoses represent a challenge for clinicians because of a lack of definitive diagnosis and related uncertainty about management.

OBJECTIVE

To review the literature on atypical melanocytic proliferations and detail synonymous terms, epidemiology, diagnostic work-up, histopathology, treatment, and prognosis.

METHODS

Databases from PubMed and Web of Science were searched for articles related to atypical melanocytic proliferations.

RESULTS

Intraepidermal melanocytic proliferations with features worrisome for possible melanoma in situ (MIS) are generally excised as for MIS. Reported rates of upstaging of such cases to invasive melanoma on review of the excision are very low. Because invasion, lymph node spread, and metastasis can occur in atypical melanocytic lesions with a thick intradermal component, these are often treated as for malignant melanoma.

CONCLUSION

Because the diagnosis dictates treatment, it is incumbent to establish a diagnosis as definitive as possible, obtaining second or third opinions and using ancillary studies when appropriate. When the diagnosis remains uncertain, it is difficult to provide guidelines for treatment. Clinical care decisions for patients with an uncertain diagnosis are best done on a case-by-case basis weighing probabilities of adverse outcomes against potential benefits and risks from various treatment options.

Pediatric and Adolescent Melanoma: A National Cancer Data Base Update

BACKGROUND

Studies suggest that the biology of pediatric and adolescent melanoma differs from that of adult disease. We report the largest series to date examining the natural history of pediatric and adolescent melanoma. We aim to elucidate the natural history of pediatric and adolescent melanoma and to examine the appropriateness of diagnostic and therapeutic modalities developed for adults and that are currently being used in children.

METHODS

A retrospective cohort study was conducted of patients with an index diagnosis of cutaneous non-metastatic melanoma from 1998 to 2011 using the National Cancer Data Base (NCDB; n = 420,416). Three age-based cohorts were analyzed: 1-10 years (pediatric), 11-20 years (adolescent), and ≥21 years (adult). Multivariate analyses were used to identify factors associated with overall survival (OS).

RESULTS

Pediatric melanoma patients have longer OS than their adolescent (hazard ratio [HR] 0.50, 95 % CI 0.25-0.98) and adult counterparts (HR 0.11, 95 % CI 0.06-0.21). Adolescents have longer OS than adults. No difference was found in OS in pediatric patients who are node-positive versus node-negative. In pediatric patients, sentinel lymph node biopsy and completion lymph node dissection are not associated with increased OS. In adolescents, nodal positivity is a significant negative prognostic indicator (HR 4.82, 95 % CI 3.38-6.87).

CONCLUSIONS

Age-based differences in melanoma outcomes warrant different considerations for diagnostic and therapeutic approaches in each group in order to maximize quality of life while minimizing complications and costs. Prospective, multicenter studies should evaluate the role of diagnostic procedures for pediatric patients.

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.

Spitzoid melanoma of childhood: a case series and review

Spitzoid melanomas (SM) and atypical Spitz tumors (AST) are rare pediatric neoplasms. We performed a retrospective, single-institution review and report our institutional experience. We identified 10 patients (median age: 12.5 years). A sentinel node biopsy (SNB) was performed in 8/10 (80%) patients, and interestingly 7/8 (87.5%) were found to be positive for malignant cells. A complete regional lymphadenectomy was performed in all SNB-positive patients, but only 2/8 (25%) were found to have additional lymph node spread. Adjuvant therapy was administered in 5/8 SLNB-positive and 2/2 (100%) regional LN-positive cases. All patients had excellent long-term outcomes (100% survival). This report highlights the excellent outcomes associated with SNB + pediatric SM and AST.

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.

Childhood melanoma: an increasingly important health problem in the USA

PURPOSE OF REVIEW

To inform pediatricians of the challenges of detection of melanoma in children and adolescents as well as to instruct on proper biopsy technique of suspicious lesions.

RECENT FINDINGS

The incidence of melanoma in children and adolescents is on the rise with an average increase of 2% per year. Rates of change are higher in adolescent girls and locations with low UV-B exposure. Standard Amelanotic, Bleeding, Bump, Color uniformity, De novo, any Diameter (ABCD) detection criteria fail to detect most childhood melanomas. Tumor thickness and sentinel lymph node status are the most important prognostic factors. Artificial tanning use is prevalent among adolescent girls and likely contributes to the growing incidence of melanoma in this group.

SUMMARY

Childhood melanoma is often amelanotic and may also appear as raised or ulcerated lesions commonly mistaken for warts or other benign skin conditions. Excision and full-thickness punch biopsies are indicated for suspicious lesions, whereas shaves and small punch biopsies are to be avoided. Pediatric patients more frequently have positive sentinel lymph nodes and increased tumor thickness, yet similar survival compared with adults.

Age as a predictor of sentinel node metastasis among patients with localized melanoma: an inverse correlation of melanoma mortality and incidence of sentinel node metastasis among young and old patients

PURPOSE

We have previously reported that older patients with clinical stage I and II primary cutaneous. Melanoma had lower survival rates compared to younger patients. We postulated that the incidence of nodal metastasis would therefore be higher among older melanoma patients.

METHODS

The expanded American Joint Committee on Cancer melanoma staging database contains a cohort of 7,756 melanoma patients who presented without clinical evidence of regional lymph node or distant metastasis and who underwent a sentinel node biopsy procedure as a component of their staging assessment.

RESULTS

Although older patients had primary melanoma features associated with more aggressive biology, we paradoxically observed a significant decrease in the incidence of sentinel node metastasis as patient age increased. Overall, the highest incidence of sentinel node metastasis was 25.8 % in patients under 20 years of age, compared to 15.5 % in patients 80 years and older (p < 0.001). In contrast, 5-year mortality rates for clinical stage II patients ranged from a low of 20 % for those 20-40 years of age up to 38 % for those over 70 years of age. Patient age was an independent predictor of sentinel node metastasis in a multifactorial analysis (p < 0.001).

CONCLUSIONS

Patients with clinical stage I and II melanoma under 20 years of age had a higher incidence of sentinel lymph node metastasis but, paradoxically, a more favorable survival outcome compared to all other age groups. In contrast, patients >70 years had the most aggressive primary melanoma features and a higher mortality rate compared to all other age groups but a lower incidence of sentinel lymph node metastasis.

Controversies in the evaluation and management of atypical melanocytic proliferations in children, adolescents, and young adults

The rising incidence of melanoma in children has brought increased attention to the clinical and pathologic diagnosis of pigmented lesions in the pediatric age group. Although melanoma in infancy and early childhood is often associated with large congenital nevi, in older children and teenagers it is most often sporadic, occurring in patients with a low skin phototype and substantial sun exposure. The rarity of this potentially fatal disorder demands astute clinical attention and a high index of suspicion for atypical lesions in pediatric patients. The challenges include the difficult decision of whether to biopsy and an often equivocal pathologic diagnosis. These diagnostically challenging and equivocal lesions lead to a degree of uncertainty regarding additional workup, prognosis, potential therapy, and follow-up plans. Consultation with a specialty dermatopathologist can be very helpful, and advanced molecular diagnostic techniques may be used in selected circumstances. Although still controversial, good evidence exists to justify a role for sentinel lymph node biopsy. Patients with atypical melanocytic proliferations have a high rate of positive sentinel lymph nodes; however, their outcomes are clearly better than in similarly staged adults with conventional melanoma. With the multiple variables involved and the relative lack of prospectively derived evidence, clinical decision-making is challenging and patients and families may experience considerable stress. This article provides data and weighs the pros and cons of a rationale for decision-making in pediatric and young adult patients with diagnostically challenging melanocytic lesions.

Dermatopathology update

This past year has seen a wealth of new developments in dermatopathology that appear to herald the dawning of a new era. Advances in molecular biology and the simplification of techniques have put molecular tests within reach of routine clinical practice and led to a radical change in our approach to lesions such as melanoma; in the future, the genetic characterization of these lesions will be an essential requirement for establishing diagnosis, prognosis, and therapy. Technological innovations have also reached dermatology departments: the introduction of ultrasound scans has propitiated the use of fine-needle aspiration cytology, which allows samples to be stained and studied immediately, thereby facilitating diagnosis of superficial and lymph-node lesions, and allowing staging of tumors such as melanoma. Targeted cancer therapies have led to the introduction of more sensitive and specific systems for identifying new targets, have reawakened interest in forgotten diseases such as aggressive basal cell carcinoma, and have led to dermatological reactions that, together with those caused by biologic drugs, we are just beginning to recognize. Consolidated techniques such as immunohistochemistry continue to advance with the addition of new antibodies that contribute considerably to improved diagnosis. New clinicopathologic diseases have also been described or characterized this year, including 2 new types of melanoma, and progress has been made in our knowledge of other diseases, such as primary cutaneous CD4(+) small/medium-sized pleomorphic T-cell lymphoma. These topics, together with new developments in adnexal tumors, alopecia, and other lesions, will be discussed in this review.

Evidence-based clinical practice guidelines on the use of sentinel lymph node biopsy in melanoma

Sentinel lymph node biopsy (SLNB) was introduced in 1992 to allow histopathologic evaluation of the "sentinel" node, that is, the first node along the lymphatic drainage pathway from the primary melanoma. This procedure has less risk of complications than a complete lymphadenectomy, and if the sentinel node is uninvolved by tumor the likelihood a complete lymphadenectomy would find metastatic disease in that nodal basin is very low. SLNB is now widely used worldwide in the staging of melanoma as well as breast and Merkel cell carcinomas. SLNB provides safe, reliable staging for patients with clinically node-negative melanomas 1 mm or greater in thickness, with an acceptably low rate of failure in the sentinel node-negative basin. Evidence-based guidelines jointly produced by ASCO and the Society of Surgical Oncology (SSO) recommend SLNB for patients with intermediate-thickness melanomas and also state that SLNB may be recommended for patients with thick melanomas. Major remaining areas of uncertainty include the indications for SLNB in patients with thin melanomas, pediatric patients, and patients with atypical melanocytic neoplasms; the optimal radiotracers and dyes for lymphatic mapping; and the necessity of complete lymphadenectomy in all sentinel node-positive patients.