Congenital melanocytic nevi (CMN) are benign pigmented lesions, present at birth or becoming apparent in the first months of life. Compared to acquired melanocytic nevi, CMN are often larger in size sometimes covering large parts of the body, contain a mottled heterogeneous morphology and may change during life. There is a large inter-individual variety in size, localization and morphology of CMN.

CMN occur in about 1% of newborns, making them core business for every dermatologist. The incidence of CMN decreases by growing size of the nevus, to 1 in 20.000 newborns for CMN that will reach at least 20 cm in adulthood. Small lesions are most often without consequence, but large CMN can carry a devastating psychosocial burden and increased risk of malignant melanoma.

After years of research, the best treatment policy in CMN is still under debate: whether or not to treat and by which therapy? Since recent studies indicate a lower malignant risk than has previously been estimated, and surgery has not been proven to lower that risk, this raises the question whether extensive surgery on CMN still benefits the patient. Patients with larger CMN need several, often painful operations, which not always improve the cosmetics results and may even result in undesirable aesthetic and functional outcomes. In addition, extensive surgery in small children may not be without risk, due to anesthetics but also because of treating large areas of skin. Unfortunately, the literature is lacking in reliable data on patient-important outcomes (like aesthetics, functionality, patient satisfaction, treatment-related quality of life) and risks of treatment. These uncertainties put a large burden on patients with CMN and their parents, added to the cosmetic burden and fear of malignancy they already have with a CMN.

We can only solve this situation by paying more attention to patient-important outcomes and safety of treatments. Therefore, to solve the treatment dilemma and improve the life of patients with CMN, our goal is to define a core set of patient-important outcome measurements that can be used in the follow-up of the patients before, during and after the treatment.

This project is the initiative of an international collaboration. To reach the core set of criteria literature reviews will be performed, and subsequently the group of international experts in CMN (both physicians and patients) will reach consensus on the patient-important outcome measures by using the Delphi method. If needed, validation studies on outcome measure(s) will be performed within the CMN population. We will develop a digital personal health record plan including tools to easily and safely register outcomes and clinical data in patients. This format for a digital registry will be made available internationally in order to facilitate international implementation.

Once defined, the developed core set of measures can also be used in patients with other diseases with visible anomalies. Furthermore, the digital registry integrated in a personal health record of the patient provides a format that can also be used for many other diseases, like rare dermatoses.

Once consensus is reached and the core set of measures is established, the core set will be promoted internationally by means of international publication(s), and within nations by and to the specific experts enrolling patients into the registries. Furthermore the performed reviews and studies will be published in international journals.


As stated before, broad international implementation of the results of this project is mandatory in order to reach our goals. To facilitate easy registration on outcome measures we will create a digital patient-centered CMN Personal Health Record and CMN research database, based on the DermHome model ( is a website in knowledge distribution in the Netherlands, which includes a symptoms check to enable patients, parents and professionals to find their diagnosis, self-management tools and treatment plans used both for (transmural) patient care, including also a treatment plan on CMN with a tool to predict the expected diameter at adult age and uploading photographs. Within this platform all clinical data on CMN patients, both patient- and physician-entered data, can be collected and data are protected.


Steps within this project:

  • define and install the definite international expert group to be involved in the consensus meetings
  • perform a systematic review on all outcome measures used in publications on therapies in CMN
  • reach consensus on the domains to be included in the core outcome set
  • perform review(s) on outcome measures to measure the domain(s) if needed
  • reach consensus on the outcome measures to be included in the core set
  • if possible validate possible invalidated outcome measures in the CMN population
  • start implementation of the core set of standardized and validated outcome measures in CMN internationally, to be included in national prospective registries on CMN
  • provide a digital personal health record where data of CMN patients can be registered by patients and professionals


Author: Prof S. Pasmans