556 CLINICAL REPORT
ActaDV ActaDV Advances in dermatology and venereology Acta Dermato-Venereologica
Dysplastic vs. Common Naevus-associated vs. De novo Melanomas: An Observational Retrospective Study of 1,021 Patients
Alejandro MARTIN-GORGOJO 1, Celia REQUENA 2, Zaida GARCIA-CASADO 3, Victor TRAVES 4, Rajiv KUMAR 5 and Eduardo
NAGORE 2, 6 1
Dermatology Department, Gregorio Marañon General University Hospital & Hospital Dermatológico Internacional, Madrid, 2 Dermatology Department, 3 Molecular Biology Laboratory and 4 Pathology Department, Instituto Valenciano de Oncología, Valencia, Spain, 5 Division of Molecular Genetic Epidemiology, German Cancer Research Center, Heidelberg, Germany, and 6 School of Medicine, Universidad Católica de Valencia“ San Vicente Ferrer”, València, Spain
The aim of this case-case study was to determine the differences between dysplastic and common naevusassociated melanomas( NAM) and de novo melanomas. A total of 1,021 prospectively collected patients with invasive cutaneous melanoma from an oncology referral centre were included in the study. Of these, 75.51 % had de novo melanomas, 12.93 % dysplastic NAM, and 11.56 % common NAM. Dysplastic NAM, compared with de novo melanomas, were associated with intermittently photo-exposed sites, atypical melanocytic naevi, decreased tumour thickness, and presence of MC1R non-synonymous variants. Common NAM presented more frequently on the trunk and were of the superficial spreading type. Comparison of dysplastic with common NAM showed significant difference only with regard to mitoses. Both subtypes of NAM shared less aggressive traits than de novo melanomas, albeit with no significant differences in survival after multivariate adjustment. In conclusion, NAM present with less aggressive traits, mostly due to a greater awareness among patients of changing moles than due to their intrinsic biological characteristics.
Key words: cutaneous malignant melanoma; naevus, pigmented; sunburn; pathology; molecular biology; MC1R.
Accepted Feb 13, 2018; Epub ahead of print Feb 13, 2018 Acta Derm Venereol 2018; 98; 556 – 562.
Corr: Eduardo Nagore, School of Medicine, Universidad Católica de Valencia, c / Quevedo, 2, ES-46001 València, Spain. E-mail: eduardo _ nagore @ ono. com
In Caucasians 5 – 85 % of cutaneous melanomas are clinically or histologically associated with pre-existing melanocytic naevi. These figures are generally lower when the remnants of pre-existing naevi are histologically determined( 4.7 – 50 %)( 1 – 3) and higher if based on patients’ recall of a clinically evident precursor lesion( 42 – 85 %)( 4, 5). A recent meta-analysis estimates that 29.1 % of melanomas probably arise from a pre-existing naevus( 6).
Melanomas that are histologically associated with melanocytic naevi( NAM) may be associated with almost any melanocytic proliferative lesion; however, they are mainly found in conjunction with dysplastic or common acquired naevi and, to a lesser extent, with congenital naevi( 7). Current evidence supports the view that NAM, regardless of the type of melanocytic benign lesions, are associated with relatively young age at diagnosis, personal history of sunburns, and high melanocytic naevi count. In addition, NAM have been linked with location( predominantly on the trunk), superficial spreading melanoma subtype, and have less surrounding solar elastosis, thinner Breslow’ s index, and absence of ulceration( 1 – 3, 8, 9). Nonetheless, many studies report no differences in ulceration( 4, 5, 10).
Common acquired naevi differ from dysplastic naevi clinically, histologically and at the molecular level, usually with divergent traits and risks that lead to their formation. It has been suggested that a medical history of high level of cumulative sun exposure plays a role in the appearance of multiple common naevi, while intense sunburns during childhood lead to the development of dysplastic naevi( 11 – 15).
To our knowledge, there are no published studies separately comparing common and dysplastic NAM with de novo melanomas. We hypothesize that, given the differences between multiple common naevi and the presence of dysplastic naevi, the melanoma associated with dysplastic and common melanocytic naevi could differ considerably, and similar differences may exist between melanoma associated with naevi and melanomas arising de novo.
The aim of this study was to assess the clinical, epidemiological, histopathological and molecular differences between common and dysplastic NAM, and between each of these subsets and de novo melanomas.
PATIENTS AND METHODS
A retrospective, observational study was performed using data( collected before the design and development of the present study) from the melanoma database of the Dermatology Department of the Instituto Valenciano de Oncologia( IVO), Valencia, Spain. This database, launched in 2000, has been regularly updated with data from newly diagnosed and follow-up melanoma patients. Clinical, epidemiological, and histological data are collected prospectively from the medical history and physical examination of patients, and the information regarding disease evolution is updated on a daily basis by dermatologists with experience in management of melanoma( 16).
The study was approved by the IVO’ s research ethics board. Informed consent was obtained previously from the participants.
Only incident patients with invasive cutaneous melanoma who had received definitive treatment at our institution between 1 doi: 10.2340 / 00015555-2908 Acta Derm Venereol 2018; 98: 556 – 562
This is an open access article under the CC BY-NC license. www. medicaljournals. se / acta Journal Compilation © 2018 Acta Dermato-Venereologica.