Analysis of pathological changes in melanoma

Melanoma lesions often occur at the junction of the dermis and epidermis. The tumor cells are similar to nevus cells, but are obviously atypia. The intercellular matrix and cells are full of melanin. According to the differences in cell morphology and the amount of melanin, they can be divided into 5 types:

1. Large epithelioid cells are common and are polygonal in shape.

2. Small epithelioid cells have large and atypical nuclei.

3. The cytoplasm of spindle cells is fibrillar and the nuclei are large and darkly stained.

4. The abnormal cells are mononuclear or multinuclear.

5. Dendritic cells are larger than normal melanocytes, with atypical nuclei. Tumor cells show a strong positive reaction to casein. When they contain little melanin, it is difficult to confirm in HE sections, so it is called "amelanotic melanoma". However, if silver staining is used, melanin can still be detected in a few cells.