Statistical Analysis of the Concordance of Immunohistochemical Stains With the Final Diagnosis in Spitzoid Neoplasms

The Spectrum of Spitz Melanocytic Lesions: From Morphologic Diagnosis to Molecular Classification

Spitz tumors represent a distinct subtype of melanocytic lesions with characteristic histopathologic features, some of which are overlapping with melanoma. More common in the pediatric and younger population, they can be clinically suspected by recognizing specific patterns on dermatoscopic examination, and several subtypes have been described. We now classify these lesions into benign Spitz nevi, intermediate lesions identified as “atypical Spitz tumors” (or Spitz melanocytoma) and malignant Spitz melanoma. More recently a large body of work has uncovered the molecular underpinning of Spitz tumors, including mutations in the HRAS gene and several gene fusions involving several protein kinases. Here we present an overarching view of our current knowledge and understanding of Spitz tumors, detailing clinical, histopathological and molecular features characteristic of these lesions.

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.

Wiesner Nevus of the Eyelid

A healthy 31-year-old female presented with an elevated vascular lesion on the right lower eyelid margin. Histology results from excisional biopsy demonstrated a range of intradermally nested atypical melanocytes with negative staining for BRCA1-associated protein 1, confirming the diagnosis of Wiesner nevus. Wiesner nevi may be a cutaneous hallmark of the BRCA1-associated protein 1-associated cancer susceptibility syndrome, and to our knowledge, this is the first report of such a lesion presenting anywhere on the ocular adnexa.

Pediatric melanoma: incidence, treatment, and prognosis

The purpose of this review is to outline recent advancements in diagnosis, treatment, and prevention of pediatric melanoma. Despite the recent decline in incidence, it continues to be the deadliest form of skin cancer in children and adolescents. Pediatric melanoma presents differently from adult melanoma; thus, the traditional asymmetry, border irregularity, color variegation, diameter >6 mm, and evolution (ABCDE) criteria have been modified to include features unique to pediatric melanoma (amelanotic, bleeding/bump, color uniformity, de novo/any diameter, evolution of mole). Surgical and medical management of pediatric melanoma continues to derive guidelines from adult melanoma treatment. However, more drug trials are being conducted to determine the specific impact of drug combinations on pediatric patients. Alongside medical and surgical treatment, prevention is a central component of battling the incidence, as ultraviolet (UV)-related mutations play a central role in the vast majority of pediatric melanoma cases. Aggressive prevention measures targeting sun safety and tanning bed usage have shown positive sun-safety behavior trends, as well as the potential to decrease melanomas that manifest later in life. As research into the field of pediatric melanoma continues to expand, a prevention paradigm needs to continue on a community-wide level.

A diagnostic algorithm for atypical spitzoid tumors: guidelines for immunohistochemical and molecular assessment

Atypical spitzoid tumors are a morphologically diverse group of rare melanocytic lesions most frequently seen in children and young adults. As atypical spitzoid tumors bear striking resemblance to Spitz nevus and spitzoid melanomas clinically and histopathologically, it is crucial to determine its malignant potential and predict its clinical behavior. To date, many researchers have attempted to differentiate atypical spitzoid tumors from unequivocal melanomas based on morphological, immonohistochemical, and molecular diagnostic differences. A diagnostic algorithm is proposed here to assess the malignant potential of atypical spitzoid tumors by using a combination of immunohistochemical and cytogenetic/molecular tests. Together with classical morphological evaluation, this algorithm includes a set of immunohistochemistry assays (p16(Ink4a), a dual-color Ki67/MART-1, and HMB45), fluorescence in situ hybridization (FISH) with five probes (6p25, 8q24, 11q13, CEN9, and 9p21), and an array-based comparative genomic hybridization. This review discusses details of the algorithm, the rationale of each test used in the algorithm, and utility of this algorithm in routine dermatopathology practice. This algorithmic approach will provide a comprehensive diagnostic tool that complements conventional histological criteria and will significantly contribute to improve the diagnosis and prediction of the clinical behavior of atypical spitzoid tumors.

Atypical Spitz Tumors: A Diagnostic Challenge

Spitzoid melanocytic lesions encompass a spectrum from benign Spitz nevi to malignant spitzoid melanomas. Spitzoid melanocytic neoplasms have significant morphologic and molecular differences from conventional melanocytic lesions, and prediction of biologic behavior and metastatic risk may be difficult. Most challenging is the atypical Spitz tumor, a borderline spitzoid melanocytic lesion of uncertain malignant potential that has overlapping histologic features with conventional Spitz nevus and spitzoid melanoma. Atypical Spitz tumors involve the sentinel lymph nodes at a greater frequency than conventional melanoma and frequently harbor chromosomal copy number changes, yet most cases follow an indolent course. Herein we review the clinical, microscopic, and molecular features of atypical Spitz tumors, including recent molecular advances, including the potential prognostic significance of chromosomal abnormalities, such as homozygous CDKN2A loss.

Spitz nevi and other Spitzoid lesions part I. Background and diagnoses

Spitz nevi are melanocytic proliferations that are characterized by spindled and/or epithelioid nevomelanocytes. First interpreted as juvenile melanoma, these lesions were later characterized as benign and were observed to affect all age groups. Today, contrasting opinions persist regarding the fundamental benignancy versus malignancy within the spectrum of Spitz tumors. Beyond clinical outcome, this controversy has also been fueled by complex and sometimes convoluted classification schemes based on pathologic characteristics. More recently, immunophenotypic and molecular analyses have begun to clarify the etiologic nature of these tumors. Recent evidence suggests that histopathologic features that suggest more aggressiveness in Spitz tumors relate to mitoses and inflammation.

Melanoma update: diagnostic and prognostic factors that can effectively shape and personalize management

Routine light microscopy remains a powerful tool to diagnose, stage and prognose melanoma. Although it is very economical and efficient, it requires a significant level of expertise and, in difficult cases the final diagnosis is affected by subjective interpretation. Fortunately, new insights into the genomic aberrations characteristic of melanoma, coupled with ancillary studies, are further refining evaluation and management allowing for more confident diagnosis, more accurate staging and the selection of targeted therapy. In this article, we review the standard of care and new updates including four probe FISH, the 2009 American Joint Commission on Cancer staging of melanoma and mutant testing of melanoma, which will be crucial for targeted therapy of metastatic melanoma.