Case #21

Frozen section diagnosis: Malignant melanoma, high risk.

Pathology and comment: Several pathologists do not diagnose malignant melanoma in frozen sections. We examine lesions suspicious of malignant melanoma. If the diagnosis of high risk melanoma (i.e. depth of invasion more than pT2) can be established on frozen section a resection with wide resection margins (2 cm) will be carried out. Histologically atypical cells or cell groups in the epidermis, mitotic figures, peritumorous round cell reactions are helpful in the diagnosis of melanoma. In some cases the diagnosis remains however difficult. We then make the diagnosis on paraffin section and a second operation will be carried out later.