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 .