The investigators' hypothesis is that cutaneous melanoma, melanoma in situ, dysplastic nevi and benign nevi all differ in not only clinical characteristics but also molecular and genotypic characteristics.

Patients with suspected primary cutaneous melanoma or a differential diagnosis, or secondary melanoma can be asked to participate in the first part of the project and patients with suspected or confirmed secondary (spread) melanoma can be included in the second part of the study. Participants included in the study answer a validated questionnaire regarding epidemiological and phenotypic factors to map medical history, prior UV exposure, family history of melanoma and/or other cancer types, skin type, smoking habits, alcohol use and quality of life.

Blood samples (whole blood) are collected before primary local excision and before secondary surgical procedures as well as during follow up of patients with secondary disease and oncologic treatment. During local excision of the primary pigmented skin lesion, full-thickness skin punch biopsies are taken by trained dermatologists. The biopsies, in the lesion and next to the lesion in the normal skin of the suspected melanoma, are taken, snap frozen and stored deep frozen. The primary lesions are documented by accurate imaging methods prior to excision.

Tissue samples from suspected or confirmed secondary melanomas are collected mainly through surgical and core needle biopsies before, during and after treatment and in case of disease progress or treatment failure. Tissue samples are snap-frozen and stored in the same way as samples from primary melanomas.

Comprehensive questionnaire based, imaging-based information, as well as histologic information provided from the pathologist report is included and stored in a secure database.

All the information in the database, along with information from molecular analysis of tissue and/or blood samples will then be used to find objective, molecular and clinical differences in melanoma, melanoma in situ, dysplastic and benign nevi along with potential information of biological aggressivity of both primary and secondary melanoma in order to find more objective diagnostic markers.

See above.

Inclusion Criteria:

• Primary part of the project: Patients in dermatological outpatient routine care in Helsingborg, Lund or Malmö Hospitals. Patients are planned for surgical excision for an equivocal pigmented skin lesion that could be a primary melanoma or a differential diagnosis of melanoma
• Secondary part of the project: . Patient, in surgical or oncological routine care in Helsingborg, Lund, Malmö or Kristianstad Hospitals. Patients are planned for surgical excision or cytological diagnostics (needle aspiration) of metastatic melanoma.
• All subjects have to be able to provide written informed consent.

Exclusion Criteria:

• Patients with lesions, primary or secondary, that are so small that a punch biopsy for the study would risk affecting the histopathological diagnosis.

Adult participants, clinical patients, recruited in the Southern Swedish health care region, Region Skane. Patients are recruited in the daily clinical practices in the departments of Dermatology, Surgery (including, ENT, Neuro, General surgery, Gynecology) and Oncology.

For now, only researchers involved in the project can access the data, but this can change after completion of the data gathering.