Dermoscopic features predicting the presence of mitoses in thin melanoma

https://doi.org/10.1016/j.jdermsci.2017.01.013Get rights and content

Highlights

  • The number of mitoses in the last AJCC classification upstage a melanoma has been included in the last AJCC classification as a factor for upstaging thin melanomas.

  • Black colour and peripheral streaks can predict the presence of mitoses in thin melanoma.

  • Atypical pigment network and brown colour are associated to thin melanoma without mitoses.

Abstract

Background

The latest AJCC classification has included the number of mitoses as a factor for upstaging thin melanomas. Meanwhile, while dermoscopy has often been used to predict melanoma thickness, its value in predicting number of mitoses remains unknown.

Objective

Our aim is to evaluate the correlation between dermoscopic features and the presence of mitoses in a consecutive cohort of thin melanomas.

Methods

A case control study has been performed to identify specific dermoscopic parameters that could differentiate thin melanomas with 1 or more mitoses per mm2 from those without mitoses.

Results

Of 177 melanomas equal to or thinner than 1 mm, 131 (74%) lesions had no mitoses and 46 (36%) lesions had at least 1 mitosis × mm2. Dermoscopic features associated with the presence of 1 or more mitoses were the following: peripheral streaks (OR 4.11; 95% CI 1.94–8.71) and black colour (OR 4.70; 95% CI; 2.28–9.68). In contrast, atypical pigment network (OR (0.30; 95% CI 0.15–0.61)) and brown colour (OR 0.36; 95% CI 0.18–0.75) were associated to melanomas without mitoses. The same variables were also associated to the increasing number of mitoses at linear regression.

Conclusion

Black colour and peripheral streaks can predict the presence of mitoses in thin melanoma, while atypical pigment network and brown colour are associated to thin melanoma without mitoses.

Introduction

Dermoscopy is a pivotal imaging tool that is currently regarded as gold standard for the preoperative diagnosis of melanoma [1]. In addition, dermoscopy provides a relatively good preoperative assessment of melanoma thickness [2], [3]. More specifically, the presence of an irregular pigment network has been significantly associated to thin melanomas (with a Breslow thickness of less than 0.75 mm), while the present of blue-white veil and atypical vascular patterns have been associated to thicker melanomas (Breslow > 0.75 mm) [2]. Another study assessing the value of dermoscopy to predict sentinel lymph node (SLN) positivity [3] demonstrated that the presence of ulceration and blotches and the absence of pigment network were more likely associated to SLN positivity.

Since the 7th AJCC classification for melanoma introduced the number of mitoses as an additional important prognostic factor for upstaging thin melanoma [4], other studies have analysed their prognostic role in melanoma patients [5]. Yet no studies have been performed to evaluate a possible correlation between certain morphologic features of thin melanoma and the presence of mitoses as measured on histopathology.

The purpose of the current study is to evaluate the correlation between dermoscopic features and the presence of mitoses in a consecutive cohort of thin melanomas.

Section snippets

Materials and methods

We conducted a retrospective analysis of clinical, dermoscopic and histopathological characteristics of thin melanomas (equal or less than 1 mm in Breslow thickness) consecutively excised at a referral pigmented lesion clinic from 2011 to 2014. Recorded clinical features of the patients included age, sex, date of diagnosis, and body site location of the primary tumour. Two dermatologists (SR and CL) jointly assessed all polarized dermoscopic images in blind for the presence/absence of dermal

Results

Dermoscopic images from 177 histopathologically proven melanomas with Breslow thickness <= 1 mm in 177 patients (119; 67% men) were analysed. Clinical and dermoscopic characteristics of the lesions are listed in Table 1, Table 2, respectively. The majority of lesions (131; 74%) had no mitosis at the histopathological examination, while 46 (36%) had at least 1 mitosis per mm2 (range, 0–11 mitoses). The average Breslow thickness was 0.57 +/− 0.22 (range 0.2–1 mm). Distribution of mitoses according to

Discussion

In the last AJCC staging system, mitotic rate and ulceration have been considered upstaging factors in melanoma thinner than 1 mm, thus influencing the decision to perform SLN biopsy [4]. The invasive technique of sentinel lymph node biopsy (SLNB) has become the standard procedure to detect occult regional node metastasis, and has a value for staging and prognosis in clinically localised primary melanomas [9], [10]. In our study, aimed to identify dermoscopic features that may predict the

References (15)

There are more references available in the full text version of this article.

Cited by (0)

View full text