Spitz nevus, Spitz tumor, and spitzoid melanoma: a comprehensive clinicopathologic overview

Rare Tumors: Opportunities and challenges from the Children's Oncology Group perspective

While all childhood cancers are rare, tumors that are particularly infrequent or underrepresented within pediatrics are studied under the umbrella of the Children's Oncology Group Rare Tumor committee, divided into the Retinoblastoma and Infrequent Tumor subcommittees. The Infrequent Tumor subcommittee has traditionally included an emphasis on globally rare tumors such as adrenocortical carcinoma, nasopharyngeal carcinoma, or those tumors that are rare in young children, despite being common in adolescents and young adults, such as colorectal carcinoma, thyroid carcinoma, and melanoma. Pleuropulmonary blastoma, gonadal stromal tumors, pancreatic tumors including pancreatoblastoma, gastrointestinal stromal tumor, nonmelanoma skin cancers, neuroendocrine tumors, and desmoplastic small round cell tumors, as well as other carcinomas are also included under the heading of the Children's Oncology Group Rare Tumor committee. While substantial challenges exist in rare cancers, inclusion and global collaboration remain key priorities to ensure high quality research to advance care.

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.

Identification of fusions with potential clinical significance in melanoma

Though uncommon in melanoma, gene fusions may have therapeutic implications. Next generation sequencing-based clinical assays, designed to detect relevant gene fusions, mutations, and copy number changes, were performed on 750 melanomas (375 primary and 375 metastases) at our institution from 2014-2021. These included 599 (80%) cutaneous, 38 (5%) acral, 11 (1.5%) anorectal, 23 (3%) sinonasal, 27 (3.6%) eye (uveal/ conjunctiva), 11 (1.5%) genital (vulva/penile), and 41 (5.5%) melanomas of unknown primary. Sixteen fusions (2%) were detected in samples from 16 patients: 12/599 (2%) cutaneous, 2/38 (5%) acral, 1/9 (11%) vulva, 1/23(4.3%) sinonasal; and 12/16 (75%) fusions were potentially targetable. We identified two novel rearrangements: NAGS::MAST2 and NOTCH1::GNB1; and two fusions that have been reported in other malignancies but not in melanoma: CANT1::ETV4 (prostate cancer) and CCDC6::RET (thyroid cancer). Additional fusions, previously reported in melanoma, included: EML4::ALK, MLPH::ALK, AGAP3::BRAF, AGK::BRAF, CDH3::BRAF, CCT8::BRAF, DIP2B::BRAF, EFNB1::RAF1, LRCH3::RAF1, MAP4::RAF1, RUFY1::RAF1, and ADCY2::TERT. Fusion positive melanomas harbored recurrent alterations in TERT and CDKN2A, among others. Gene fusions were exceedingly rare (0.2%) in BRAF/RAS/NF1-mutant tumors and were detected in 5.6% of triple wild-type melanomas. Interestingly, gene rearrangements were significantly enriched within the subset of triple wild-type melanomas that harbor TERT promoter mutations (18% versus 2%, p < 0.0001). Thirteen (81%) patients were treated with immunotherapy for metastatic disease or in the adjuvant setting. Six of 12 (50%) patients with potentially actionable fusions progressed on immunotherapy, and 3/6 (50%) were treated with targeted agents (ALK and MEK inhibitors), 2 off-label and 1 as part of a clinical trial. One patient with an AGAP3::BRAF fusion positive melanoma experienced a 30-month long response to trametinib. We show that, detecting fusions, especially in triple wild-type melanomas with TERT promoter mutations, may have a clinically significant impact in patients with advanced disease who have failed front-line immunotherapy.

Ungual Spitz Nevus: Description of Dermoscopic Data

INTRODUCTION

Spitz nevus is an uncommon, benign melanocytic proliferation that primarily appears on face, trunk or lower extremities of children. This lesion may share clinical and microscopical characteristics with melanoma, making it a diagnostic and management challenge.

CASE REPORT

A 13-year old male presented with an asymptomatic chronic dermatosis located on the third left-hand nail. Cutaneous examination revealed a homogeneous dark brown melanonychia which extended up to the cuticle. Upon dermoscopy, longitudinal bands measuring less than 3 mm wide of heterogeneous colors ranging from light to dark brown, and positive Hutchinson's sign were observed.

DISCUSSION/CONCLUSION

We report the second case of a Spitz nevus ungually localized which strongly resembled an ungual melanoma with a positive Hutchinson's sign upon dermoscopy. Describing the infrequent presentation and location of the Spitz nevus poses an opportunity to establish diagnostic and management criteria in the near future.

Dermoscopy of Small Diameter Melanomas with the Diagnostic Feasibility of Selected Algorithms-A Clinical Retrospective Multicenter Study

Simple Summary

The early detection of melanoma determines the recovery of the patient. Dermoscopy, which is one of the diagnostic tools for pigmented lesions, is characterized by high sensitivity and specificity, giving the clinician the possibility to detect the presence of abnormal structures before their clinical presentation. There are a small number of dermoscopic analyses of pigmented lesions of less than 6 mm in diameter in the published literature. The authors attempted to identify characteristic dermoscopic structures typical for melanomas of less than 5 mm in diameter in comparison with a group of melanomas exceeding this dimension at an identical clinical stage. It was found that dermoscopy in the secondary prevention of micromelanomas (appearing mainly as brown lesions) revealed the presence of dotted or polymorphous vessels, with architectural disorder in half of cases. Moreover, spitzoid, multicomponent asymmetric or nonmelanoma-specific patterns prevailed. Knowledge of these dermoscopic features brings the clinician closer to an early diagnosis of melanoma with a diameter of 5 mm or less.

Abstract

Objective: The aim of the study was to verify two hypotheses. The first concerned the possibility of diagnostic dermoscopic differentiation between cutaneous melanomas of the histopathological category in situ (pTis) and thin melanomas (pT1a) in terms of their diameter. The second assessed the diagnostic feasibility of two dermoscopic algorithms aiming to detect ≤ 5.0 mm-sized melanomas histopathologically confirmed as pTis and pT1a. Methods: Dermoscopic images of consecutive cases of histopathologically confirmed melanomas were evaluated by three independent investigators for the presence of the predefined criteria. The melanomas were subdivided according to their diameter into small melanomas, so-called micromelanomas (microM)—sized ≤ 5.0 mm and >5.0 mm, according to published definitions of small melanocytic lesions. The Triage Amalgamated Dermoscopic Algorithm (TADA) and the revisited 7-point checklist of dermoscopy (7-point) algorithm were chosen for the diagnostic feasibility. Odds ratios and corresponding 95% confidence limits (CL) were calculated using the logistic regression adjusted for age for the melanoma-specific dermoscopic structures, the dermoscopic patterns and the diagnostic feasibility of the 7-point checklist and TADA algorithms. The p-values of the results were corrected using the Bonferroni method. Results: In total, 106 patients with 109 melanomas, 50 sized ≤ 5.0 mm and 59 exceeding the diameter of 5.0 mm, were retrospectively analyzed. The prevalent general pattern of microM was the spitzoid one (48% vs. 11.86%, p = 0.0013). Furthermore, 40% of microM vs. 6.78% melanomas sized > 5.0 mm (p = 0.0023) did not present melanoma-specific patterns. The asymmetric multicomponent pattern was present in 64.41% melanomas sized > 5.0 mm and in 26.00% microM (p = 0.0034). The asymmetry of structures or colors was detected in 56% microM vs. 89.83% (p = 0.0020) and 56% microM and 94.92% (p = 0.000034) melanoma sized > 5.0 mm, respectively. The differences in frequency of the detected dermoscopic structures specific to melanomas revealed that microM are almost deprived of negative networks (p = 0.04), shiny white structures (p = 0.0027) and regression features (p = 0.00003). Neither prominent skin markings nor angulated lines were found in the entire study group. Out of the vascular structures, microM presented only dotted (32%) or polymorphous (28%) vessels, although more rarely than melanomas sized > 5.0 mm (66.1% p = 0.017 and 49% p > 0.05, respectively). The diagnostic feasibility revealed a score ≥ 3 of the 7-point algorithm (indicative for malignancy) in 60% microM and 98.31% melanomas sized > 5.0 mm (p = 0.000006). The TADA algorithm revealed melanoma-specific patterns in 64% microM and 96.61% > 5.0 mm-sized melanomas (p = 0.00006) and melanoma-specific structures in 72% and 91.53% (p > 0.05), respectively. Conclusion: In the dermoscopy, 40% of micromelanomas histopathologically staged as pTis and pT1a did not reveal melanoma-specific patterns. Among the general melanocytic patterns, the spitzoid one was the most frequently found in melanomas sized ≤ 5.0 mm. The 7-point checklist and TADA dermoscopic algorithms were helpful in the identification of the majority of melanomas sized ≤ 5.0 mm.

Pseudomalignancies in Children: Histological Clues, and Pitfalls to Be Avoided

The term “pseudomalignancy” covers a large, heterogenous group of diseases characterized by a benign cellular proliferation, hyperplasia, or infiltrate that resembles a true malignancy clinically or histologically. Here, we (i) provide a non-exhaustive review of several inflammatory skin diseases and benign skin proliferations that can mimic a malignant neoplasm in children, (ii) give pathologists some helpful clues to guide their diagnosis, and (iii) highlight pitfalls to be avoided. The observation of clinical–pathological correlations is often important in this situation and can sometimes be the only means (along with careful monitoring of the disease’s clinical course) of reaching a firm diagnosis.

Spitz nevi in African Americans: A retrospective chart review of 11 patients

BACKGROUND

Spitz nevi are benign melanocytic neoplasms that typically present as rapidly growing solitary lesions on the head, neck, or lower extremities. Very rare reports have been described in African Americans.

METHODS

A single-institution 29-year retrospective review of African American patients diagnosed with Spitz nevi was thoroughly analyzed in order to characterize these rare clinical and histopathologic presentations.

RESULTS

Eleven African Americans with spitzoid lesions were identified. Seven (64%) cases were in pediatric patients and nine (82%) were in females. Most lesions were hyperpigmented (73%) and elevated (82%). Six (55%) were compound Spitz nevi, three (27%) were dermal Spitz nevi, and two (18%) were junctional Spitz nevi. Two lesions had more than one atypical feature. Histopathologically, common features were symmetry, sharp circumscription, pagetoid spread (55%) with most being centrally, predominance of epithelioid cells (64%), Kamino bodies (45%), slight pigmentation (46%), maturation of dermal component with depth, and lack of subcutaneous fat involvement or ulceration. Excision was performed on all patients and there were no recurrences although follow-up was limited.

CONCLUSION

Awareness of the possibility and various presentations of Spitz nevi in African Americans will help prevent misdiagnosis.

A sixteen-year single-center retrospective chart review of Spitz nevi and spitzoid neoplasms in pediatric patients

BACKGROUND

Spitzoid neoplasms in pediatric patients pose an interesting challenge for clinicians. More data on the clinical, histologic, and molecular characteristics of these lesions are necessary to distinguish features that may portend recurrence or malignant behavior to help determine future treatment guidelines in pediatric patients.

METHODS

Institutional Review Board approval was obtained from Children's Hospital of Wisconsin to conduct a retrospective analysis of spitzoid neoplasms. Patients with biopsied or excised spitzoid neoplasms between 01/01/2000 and 08/01/2016 were included. Pertinent clinical and histologic data were collected. Atypical, unusual, or diagnostically uncertain lesions were selected for re-review.

RESULTS

266 lesions from 264 patients were included. 243 were classified as benign (91.35%), 22 as atypical (8.27%), and 1 as spitzoid melanoma (0.38%). No clinical or histologic variables were found to be statistically significant between the benign Spitz, atypical Spitz, and spitzoid melanoma cohorts. No known deaths occurred.

CONCLUSION

Our findings highlight the extreme variability of spitzoid neoplasms clinically and histologically. Importantly, this study demonstrates that the vast majority of spitzoid neoplasms in pediatric populations are benign and supports conservative management of spitzoid lesions in children.

Pathology of Melanoma

Melanoma is an aggressive malignancy arising from melanocytes in the skin and rarely in extracutaneous sites. The understanding of pathology of melanoma has evolved over the years, with the initial classifications based on the clinical and microscopic features to the current use of immunohistochemistry and genetic sequencing. The depth of invasion and lymph node metastasis are still the most important prognostic features of melanoma. Other important prognostic features include ulceration, lymphovascular invasion, mitosis, and tumor-infiltrating lymphocytes. This article reviews the pathology of melanoma and its precursor lesions, along with the recent advances in pathologic diagnosis of melanoma.

The prevalent dermoscopic criterion to distinguish between benign and suspicious pink tumours

BACKGROUND

Pink skin tumours are difficult to differentiate, clinically and dermoscopically. In previous studies, mainly focused on pigmented lesions, pattern analysis provided the best sensitivity and specificity values, as compared to other algorithms. These findings suggest that the global dermoscopic appearance, based on the evaluation of prevalent features, could represent a valuable and practical approach even when dealing with pink lesions.

OBJECTIVE

In this study, we aimed to evaluate the diagnostic accuracy of a new dermoscopic approach for pink tumours based on the prevalent criterion, as compared to a standard diagnostic method (Menzies algorithm).

METHODS

The databases of two referral centres were retrospectively evaluated to retrieve dermoscopic images of amelanotic/hypomelanotic skin lesions. Two experts in dermoscopy, blinded for the final diagnosis and for clinical and demographic information, evaluated separately dermoscopic pictures of 1000 lesions according to the Menzies score and to the prevalent criterion method.

RESULTS

According to the high sensitivity model of the Menzies score, 129 (12.9%) lesions were considered as non-suspicious (of which 16 were false negative) and 871 (87.1%) as suspicious (of which 212 were false positive), with 97.6% sensitivity and 34.8% specificity. According to the high specificity model, 370 (37%) lesions were evaluated as non-suspicious (of which 105 were false negative) and 630 (63%) as suspicious (of which 60 were false positive), with 84.4% sensitivity and 81.5% specificity. Concerning the prevalent criterion method, 316 (31.6%) lesions were evaluated as non-suspicious (of which 46 were false negative) and 684 (68.4) as suspicious (of which 55 were false positive), with 93.2% sensitivity and 83.1% specificity.

CONCLUSIONS

This study demonstrated that focusing on the prevalent dermoscopic features could allow to detect malignant pink tumours with similar sensitivity but higher specificity than using the conventional Menzies scoring system.

Clinicopathologically problematic melanocytic tumors: a case-based review

Background

In spite of recent advances in the histopathological and molecular diagnosis of melanocytic neoplasms, a certain proportion of these lesions remain a daunting challenge for both the clinician and the pathologist.

Objectives

To emphasize the importance of close collaboration between clinicians and pathologists in case of problematic melanocytic lesions.

Patients

We report and discuss 5 problematic scenarios of melanocytic lesions, including tumoral melanosis, nevoid melanoma, lentiginous melanoma, spitzoid melanoma and BAPoma that may pose diagnostic difficulties in our practice.

Conclusions

Clinico-dermoscopic-pathological correlation, with incorporation of all the available data, in problematic melanocytic skin neoplasms is of paramount importance for accurate diagnosis.

The large spectrum of Spitzoid tumors: a retrospective survival study

BACKGROUND

There is no universally-accepted classification of Spitzoid tumors. This makes it difficult to assign a correct diagnosis and select a treatment that minimizes the risk of overestimating, or worse, underestimating, the malignant potential of these tumors. The aim of this study was to describe the clinical-pathological and epidemiological features of Spitzoid tumors, as well as to assess mortality in these patients.

METHODS

This retrospective cohort study looked at data on Spitzoid tumors excised in 1999-2012 at the Dermatologic Clinic of the Turin University Hospital. Spitzoid melanoma specific survival curves were generated with the Kaplan-Meier method and compared using the log-rank test.

RESULTS

In this time period, 1663 lesion were described at the pathologic report as Spitzoid. 262 (15.75%) were Spitz nevi, 307 (18.46%) Reed nevi, 827 (49.73%), 810 (48.71%) Spitzoid dysplastic nevi, 17(1.02%) atypical Spitzoid tumors, and 267 (16.06%) Spitzoid melanomas. Median follow-up time was 9 years. Out of the entire cohort only 24 patients died from melanoma. All of them received a diagnosis of Spitzoid melanoma. None of the patients with a diagnosis of not melanoma Spitz tumor died for melanoma during the follow-up.

CONCLUSIONS

In the large majority of the cases, Spitz tumor should be considered as benign lesion and excised only if melanoma features are seen. The used clinical pathological classification avoid misdiagnoses, inappropriate treatment and the risk of death for melanoma.

Melanocytic nevi and melanoma: unraveling a complex relationship

Approximately 33% of melanomas are derived directly from benign, melanocytic nevi. Despite this, the vast majority of melanocytic nevi, which typically form as a result of BRAF^V600E-activating mutations, will never progress to melanoma. Herein, we synthesize basic scientific insights and data from mouse models with common observations from clinical practice to comprehensively review melanocytic nevus biology. In particular, we focus on the mechanisms by which growth arrest is established after BRAF^V600E mutation. Means by which growth arrest can be overcome and how melanocytic nevi relate to melanoma are also considered. Finally, we present a new conceptual paradigm for understanding the growth arrest of melanocytic nevi in vivo termed stable clonal expansion. This review builds upon the canonical hypothesis of oncogene-induced senescence in growth arrest and tumor suppression in melanocytic nevi and melanoma.

Spitz Nevi and Other Spitzoid Neoplasms in Children: Overview of Incidence Data and Diagnostic Criteria

Spitz nevi are benign melanocytic neoplasms characterized by epithelioid or spindle melanocytes or both. In some rare cases their presentation overlaps with the clinical and histopathologic features of malignant melanoma, so a differential diagnosis can be difficult to make. Intermediate forms between Spitz nevi and malignant melanoma, with unpredictable behavior, have been called atypical Spitz tumors. A literature search was performed to review the clinical, dermoscopic, genetic, and histopathologic aspects of spitzoid tumors. Spitz nevi mainly occur in children, with no predilection for sex, and in young women. Common sites are the head and lower arms, where Spitz nevi present as pink nodules or hyperpigmented plaques. Spitzoid lesions may have diverse dermoscopic patterns: vascular, starburst, globular, atypical, reticular, negative homogeneous, or targetoid. The management of spitzoid lesions can be invasive or conservative; surgical excision is usually reserved for those with doubtful features, whereas clinical and dermoscopic follow-up is preferred for typical pediatric Spitz nevi. The role of sentinel lymph node biopsy in atypical Spitz tumors is debated. Immunohistochemistry and new molecular techniques such as comparative genomic hybridization, polymerase chain reaction, and fluorescence in situ hybridization offer new diagnostic perspectives, investigating genetic alterations that are specific for malignant melanoma or for Spitz nevi.

Dermoscopy of difficult-to-diagnose Melanomas

Dermoscopy is a non-invasive procedure that allows the evaluation of cutaneous lesions, and is considered to be a useful tool that improves the diagnostic accuracy of melanoma. Many dermoscopic criteria of melanoma have been established and several algorithms have been created for melanoma detection. However, the recognition of some melanomas remains challenging. Melanomas on specific body sites, melanomas in patients with multiple atypical moles, and nodular melanomas represent the most difficult-to-recognize melanoma subtypes, since they typically lack the “classic” melanoma-specific criteria. This paper provides an update on dermoscopy of difficult-to-diagnose melanomas by summarizing the newest data. Lastly, we highlight the importance of digital dermoscopy in the follow-up of melanocytic lesions for the detection of incipient melanomas while maintaining a low excision rate.

Imaging mass spectrometry assists in the classification of diagnostically challenging atypical Spitzoid neoplasms

BACKGROUND

Previously, using imaging mass spectrometry (IMS), we discovered proteomic differences between Spitz nevi and Spitzoid melanomas.

OBJECTIVE

We sought to determine whether IMS can assist in the classification of diagnostically challenging atypical Spitzoid neoplasms (ASN), to compare and correlate the IMS and histopathological diagnoses with clinical behavior.

METHODS

We conducted a retrospective collaborative study involving centers from 11 countries and 11 US institutions analyzing 102 ASNs by IMS. Patients were divided into clinical groups 1 to 4 representing best to worst clinical behavior. The association among IMS findings, histopathological diagnoses, and clinical groups was assessed.

RESULTS

There was a strong association between a diagnosis of Spitzoid melanoma by IMS and lesions categorized as clinical groups 2, 3, and 4 (recurrence of disease, metastases, or death) compared with clinical group 1 (no recurrence or metastasis beyond a sentinel node) (P < .0001). Older age and greater tumor thickness were strongly associated with poorer outcome (P = .01).

CONCLUSIONS

IMS diagnosis of ASN better predicted clinical outcome than histopathology. Diagnosis of Spitzoid melanoma by IMS was strongly associated with aggressive clinical behavior. IMS analysis using a proteomic signature may improve the diagnosis and prediction of outcome/risk stratification for patients with ASN.

Spitz/Reed nevi: a review of clinical-dermatoscopic and histological correlation

Background:

Spitz/Reed nevi are melanocytic lesions that may mimic melanoma at clinical, dermatoscopic and histopathological levels. Management strategies of these lesions remain controversial.

Objectives:

We aim a correlation among clinical-dermatoscopic and histological features of a series of Spitz/Reed nevi diagnosed during 7 years at the Department of Dermatology.

Methods:

Clinical, dermatoscopic and histological features of Spitz/Reed nevi diagnosed at our tertiary hospital from 2008 to 2014 were reviewed in order to seek correlation.

Results:

All described dermatoscopic patterns for Spitz/Reed nevi were found among the 47 enrolled patients; starburst and atypical/multicomponent patterns prevailed (57.4%). Reticular pattern predominated among children younger than 12 years, whereas homogeneous pattern was more frequent in patients older than 12 years, although these differences were not statistically significant (P=0.785). Among histological atypical lesions, all dermatoscopic patterns were represented, but the atypical/multicomponent predominated (56.3%). Two out of 11 dermatoscopically atypical lesions did not show histopathological counterpart.

Conclusions:

The excision of Spitz/Reed nevi in adults is supported, given the inability to accurately predict those with histopathological atypia, based on clinical and dermatoscopic features, which may raise concern about malignancy.

Clinical and dermoscopic features of atypical Spitz tumors: A multicenter, retrospective, case-control study

BACKGROUND

Few studies have described the clinical and dermoscopic features of atypical Spitz tumors.

OBJECTIVE

We sought to describe the clinical and dermoscopic features of a series of atypical Spitz tumors as compared with those of conventional Spitz nevi.

METHODS

This was a multicenter, retrospective, case-control study, analyzing the clinical and dermoscopic characteristics of 55 atypical Spitz tumors and 110 Spitz nevi that were excised and diagnosed histopathologically.

RESULTS

The majority of atypical Spitz tumors presented clinically as a plaque or nodule, dermoscopically typified by a multicomponent or nonspecific pattern. A proportion of lesions (16.4%) exhibited the typical nonpigmented Spitzoid pattern of dotted vessels and white lines under dermoscopy. Nodularity, ulceration, linear vessels, polymorphic vessels, white lines, and blue-white veil were associated with atypical Spitz tumors by univariate analysis, but only nodularity and white lines remained significant after multivariate analysis. In contrast, a pigmented typical Spitzoid pattern was a potent predictor of Spitz nevi, associated with 6.5-fold increased probability.

LIMITATIONS

Differentiation from Spitzoid melanoma and other nonmelanocytic lesions was not investigated.

CONCLUSION

Atypical Spitz tumors are polymorphic melanocytic proliferations with a nodular clinical appearance. Dermoscopically they demonstrate a multicomponent and nonspecific pattern. A typical nonpigmented Spitzoid pattern on dermoscopy (with dotted vessels and white lines) does not exclude atypical Spitz tumors.

Pediatric melanoma: the whole (genome) story

Pediatric melanoma is rare and given the diagnostic challenges it presents in this age group, it is difficult to interpret the literature describing its natural history and outcome. Recent genomic analysis demonstrates that conventional melanoma in children and adolescents shares many of the genomic features that have been described in adult melanoma, including BRAF mutations. Thus, this patient group should be given the opportunity to enroll in National Cancer Institute and pharmaceutically sponsored trials that incorporate novel targeted agents.

Differential diagnosis of heavily pigmented melanocytic lesions: challenges and diagnostic approach

The differential diagnosis of heavily pigmented melanocytic neoplasms includes melanoma (especially animal type), melanosis of partially or completely regressed melanoma, blue naevus (BN), pigmented Spitzoid lesions, recurrent naevus, combined naevus, pigmented spindle cell naevus, epithelioid blue naevus of the Carney complex/pigmented epithelioid melanocytoma, deep penetrating naevus, hyperpigmented scar after surgery of melanoma in which there are also melanophages and hyperpigmentation due to the minocycline, a tattoo or a hyperpigmented scar. Pathologists face challenges when evaluating a pigmented lesion, especially in a small superficial biopsy, because it is difficult to access important histopathological features to differentiate benign versus malignant melanocytic lesions. The histological features that favour a diagnosis of melanoma include dimension (>6 mm), asymmetry, poor circumscription, irregular confluent nests, confluent lentiginous junctional melanocytic proliferation, lack of maturation with descent in the dermis, suprabasal pagetoid melanocytes, asymmetrical distribution of melanin pigment, cytological atypia, dermal mitotic figures, asymmetrical dermal lymphocytic infiltrate and necrosis.

Melanocytic tumors with intraepidermal melanophages: a report of five cases with review of 231 archived cutaneous melanocytic tumors

Dermal melanophages are frequently encountered in both benign melanocytic nevi and malignant melanoma. In contrast, intraepidermal melanophages (IEM) are under-recognized in melanocytic lesions and their biologic significance is not understood. Herein, we report the clinical and histopathologic features of five melanocytic lesions featuring IEM encountered prospectively in our dermatopathology practice at the University of Chicago. Two hundred and thirty-one (231) archived skin primary melanocytic proliferations were also investigated retrospectively in a de-identified, archival teaching set collection. Nineteen of 231 of the archived cases were positive for IEM. Among the total 24 IEM-positive cases (5 prospective and 19 archived cases), 13 were categorized as Spitz nevi (p < 0.0001) and 3 as atypical Spitz tumors (p = 0.0152). Fourteen of 24 cases with IEM also exhibited intracorneal melanocytes (p < 0.0001). IEM are evidently not rare, especially in spitzoid melanocytic neoplasms. IEM in our series were significantly correlated with intracorneal melanocytosis, possibly indicating an association between IEM and suprabasal melanocytosis and/or transepidermal elimination of melanocytes.

Update on melanocytic nevi in children

A new or changing melanocytic nevus in a child or adolescent often leads to concern in parents and physicians. To avoid undue alarm and unnecessary procedures, dermatologists should be aware of the natural history and clinical spectrum of nevi in pediatric patients, as well as findings that are potentially worrisome in this age group. This review provides an update on melanocytic nevi in children, focusing on their dynamic evolution over time, molecular insights into nevogenesis, and phenotypic markers for increased risk of melanoma in adolescence and adulthood. Special considerations for Spitz nevi and nevi located in particular sites (eg, scalp, acral, genital) are highlighted. Current understanding of the risks associated with congenital melanocytic nevi of different sizes and strategies for the management of children with numerous acquired nevi, Spitz nevi, and congenital nevi are also discussed.