Dysplastic nevus : Clinical features and usefulness of dermoscopy

Dermoscopic, Histological, Confocal Microscopy Correlation of Atypical-Dysplastic Melanocytic Nevi

INTRODUCTION

The term "atypical melanocytic nevus" (AMN) is used as a synonym for dysplastic nevus (DN) in clinical practice. Although the criteria for diagnosis of AMN/DN by the Agency for Research on Cancer helps to differentiate AMN/DN from common acquired nevi, they do not have high degrees of specificity, as they are similar to those used for the diagnosis of melanoma.

OBJECTIVES

In this retrospective study we evaluated the correlation and diagnostic concordance of dermoscopy, confocal microscopy, and histological examination in 50 AMN.

METHODS

A graded scale was used to compare histological examination with dermoscopy and confocal microscopy. Low magnification histological images of only the central part of lesions were examined. This allowed histological diagnoses based almost exclusively on architectural criteria instead of simultaneously architectural and cytological, as in the global histological examination.

RESULTS

Our data demonstrate that the diagnostic accuracy of dermoscopy and confocal microscopy diagnosis of the clinical aspects of AMN/DN as nevi or melanomas tends to be equivalent, being fair for nevi and excellent for melanomas. The total percentage of AMN suggested that the accuracy of confocal microscopy in the diagnosis of melanoma (86.7%) is greater than that of dermoscopy (73.3%).

CONCLUSIONS

This study demonstrated that diagnostic assessments of AMN/DN by dermoscopy and confocal microscopy are accurate and often coincide with those of histological examination and that their combined use helps to better manage and monitor these patients by facilitating early detection of melanomas and reducing unnecessary excisions of benign melanocytic lesions.

A Single-Institution Cohort Study With Nevi of Special Site: Recurrence, Progression to Melanoma, and Patterns of Management

ABSTRACT

Nevi of specialized sites (NOSS) occur on the scalp, ears, flexural, acral, and genital areas and display atypical clinical and histologic features. We assessed NOSS recurrence and progression to melanoma, management patterns, and associations between histologic features and treatment recommendations. We queried all histologic diagnoses of NOSS (n = 275) from 2012 to 2017 from a large U.S. academic medical center with reference dermatopathology laboratory and matched these to clinical records. A blinded panel of dermatopathologists re-evaluated lesions, catalogued histologic findings, and gave management recommendation. Associations with dermatopathologist decision and concordance between new and original recommendations were assessed. Of 117 cases with follow-up, 2 locally recurred (1.46%) and none eventuated in melanoma. Clinical features were not associated with original treatment recommendations. After histopathologic review, large melanocytes [odds ratio ratio (ORR) = 8.00, 95% CI, 1.35-47.4] and junctional mitotic figures (ORR = 65.0, 6.5-650) predicted excision recommendation. Likewise, accumulation of many (>9) high-risk features was associated with excision recommendation. Panel review changed treatment recommendation in 27% of cases. Fair concordance existed between original and panel recommendations (κ = 0.29, 0.15-0.44). The low rate of recurrence and lack of melanoma occurrence suggest that despite an atypical clinical and histopathologic appearance, these nevi have limited potential for malignant transformation. Histopathologic findings seem to be principal drivers behind the recommendation for excision in this analysis. Variability existed in treatment recommendations; the panel's consensus recommendation tended to downgrade treatment. This highlights the importance of further outcomes-based studies to identify true high-risk features and refine management guidelines.

A Case Report on the Dermoscopic Features of Spark's Nevus

Spark's nevus is a compound word composed of Spitz nevus and Clark's nevus. It is one of the combined melanocytic nevi which is more common in female and usually presents as a sharp circumscribed hyperpigmented macule on the lower extremities. On histopathologic findings, both cytologic features of Spitz nevus characterized as large spindle or epithelioid melanocytes containing large nuclei with abundant cytoplasm, and architecture of Clark's nevus characterized as elongation of rete ridges, bridging of the nests, concentric and lamellar fibrosis can be seen. A 24-year-old female presented with an asymptomatic, solitary, dark-brown-colored papule surrounded by brownish patch that looked similar to dysplastic nevus or malignant melanoma on the buttock. On dermoscopic examination, it showed brown-to-black globules, diffuse homogenous pigmentation with blue-white structures, and a surrounding brownish reticular pattern that faded away. On histopathologic findings, overall asymmetrical structure, epithelioid large melanocytes containing large nuclei with abundant cytoplasm, and Kamino body were seen in the central portion. Also, lentiginous hyperplasia, bridging of the nests composed of melanocytes containing foamy cytoplasm, concentric and lamellar fibrosis along with the elongation of rete ridge, and perivascular lymphocytic infiltration were seen in the peripheral portion. The diagnosis of Spark's nevus was made. Following its definition, this combined nevus is diagnosed histopathologically, but the clinicodermoscopic features have not been well described. Herein, we report a case of Spark's nevus in which dermoscopy was helpful for differentiating it from malignant melanoma.