Cutaneous malignant melanoma in situ: A Danish cross-sectional study on patient and tumour characteristics in 144 cases: Population-based cross-sectional study

Abstract Introduction Cutaneous malignant melanoma in situ (MIS) has not been subject to much attention or investigation. Little is known of the characteristics of patients and tumours. The aim of this study was to elucidate important tumour characteristics in patients treated for MIS. Methods Based on data from the Danish Melanoma Register, patient and tumour characteristics were evaluated in a cross-sectional study including all patients diagnosed with cutaneous malignant melanoma in Health care Region Zealand between 2012 and 2013. Results A total of 144 patients were identified with malignant melanoma in situ; more females were affected than males, and the males were older than females. Patients with lentigo maligna were older than patients with superficial spreading MIS, which were predominantly found in the head and neck region. Among patients treated for MIS, 28% were previously treated for other skin malignancies. Conclusion The anatomical distribution of MIS differed with patient age and tumour subtype. The anatomical distribution was different in comparison to invasive malignant melanomas, and MIS cases were generally older. This suggests a non-linear relation between malignant melanoma in situ and invasive malignant melanoma.