The superficial atypical Spitz tumor and malignant melanoma of superficial spreading type arising in association with the superficial atypical Spitz tumor: A distinct form of dysplastic Spitzoid nevomelanocytic proliferation

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

Spitz nevus can clinically present either in the classical (reddish pink) or the pigmented (brownish black) variant. Dermoscopy demonstrates that the pigmented variant is much more common than the classical variant; however, none of these show dermoscopic patterns clearly distinguishable from melanoma. Even histopathologically, a clear-cut differentiation between benign and malignant spitzoid neoplasms is often difficult, so that intermediate diagnostic categories (atypical Spitz nevus and Spitz tumor) are admitted. Because of these difficulties in clinical and histopathologic evaluation, surgical excision is recommended for clinically atypical spitzoid lesions of childhood and for all spitzoid lesions of adulthood.

Molecular diagnostics for ambiguous melanocytic tumors

Certain subsets of melanocytic neoplasms are difficult to classify because of conflicting histologic features and the existence of a poorly defined intermediate grade of melanocytic tumors. The integration of molecular diagnostic information with a histologic impression may contribute significantly toward improving classification. This review discusses the development of and advances in molecular techniques, including comparative genomic hybridization and fluorescence in situ hybridization (FISH) as diagnostic and prognostic tools for melanocytic neoplasms. Further, we discuss how specific molecular aberrations identified via FISH correlate with certain morphologies in melanocytic neoplasms. We also examine the prognostic value of FISH in intermediate-grade melanocytic tumors, particularly atypical Spitz tumors.

Update in molecular diagnostics in melanocytic neoplasms

Future classification systems for melanocytic neoplasms will likely include the integration of molecular aberrations. A number of studies have shown that many gene mutations and chromosomal copy number aberrations may correlate with characteristic clinical and morphologic features for melanocytic neoplasms. This review discusses newly described familial germline mutations such as the BRCA1-associated protein-1 familial melanoma syndrome, recently described somatic mutations, and chromosomal copy number aberrations recently described in melanoma. Further, we discuss how these specific molecular aberrations correlate with specific clinical and morphologic features in melanocytic neoplasm and their implications for prognosis and molecular diagnostics. In addition, we discuss state of the art advancements in molecular diagnostics for melanocytic neoplasms and newly developed fluorescence in situ hybridization assays including the utility of fluorescence in situ hybridization for 9p21 in spitzoid melanocytic neoplasms. Lastly, we discuss a phenomenon known as paradoxical activation of wild-type BRAF seen in patients treated with vemurafenib and some potential clinical presentations of this process.

Outcomes in pediatric melanoma: comparing prepubertal to adolescent pediatric patients

OBJECTIVE

The aim of this study was to determine the influence of age on outcome in pediatric melanoma patients and to identify factors associated with positive lymph node status in this population.

METHODS

A retrospective review of a prospective pediatric melanoma database, using sentinel lymph node biopsy (SLNB), from 1992 to 2006, identified 109 patients with the primary diagnosis of melanoma. Patient age was dichotomized as prepubescent (<10 years of age) and adolescent (≥10-18 years of age). Factors investigated included patient race, sex, and lymph node status and tumor thickness, Spitzoid or Non-Spitzoid histology, radial growth phase, and vascular invasion. The Fisher's exact test was used to compare patient groups. Time-to-event analysis was performed using the Kaplan-Meier method.

RESULTS

There were 25 prepubescent and 84 adolescent patients. Prepubescent patients were more often non-White, had greater tumor thickness, more spitzoid tumors and more vascular invasion. Ten-year overall survival (OS) was 89% and 10-year event-free survival (EFS) was 73%. Among 57 patients who had an SLNB, prepubertal patients had a higher percentage of sentinel lymph node positivity. The odds having a positive SLNB decreased by 13% each year with increasing age. Patients with a tumor thickness ≥2.01 mm had higher odds of having a positive lymph node compared with those patients with a tumor thickness ≤1.0.

CONCLUSIONS

This is the largest known study of prepubertal melanoma patients. Although OS and EFS did not differ by age groups, younger ages showed increased risk of lymph node metastasis and thicker tumors. This suggests that the younger pediatric patients may have a disease that differs biologically from that of the older pediatric patients.

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.

De novo intraepidermal epithelioid melanocytic dysplasia: an emerging entity

De novo intraepidermal epithelioid melanocytic dysplasia represents a distinctive form of intraepidermal melanocytic dysplasia. Although these lesions are atypical, they are not diagnostic of melanoma. They are considered a part of the atypical mole phenotype and may define a point in the natural course of melanomagenesis.