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Melanocytic lesions potpourri

Lentigo maligna

Basically, lentigo maligna has increase in melanocytes.  Morphologically, melanocytes has cytoplasmic halo while basal cells do not have halo.  However, melanocytes may pass melanin to basal cells, causing confusion.  Therefore to disprove lentigo maligna, one has to do S100 IHC stain.

Junctional and compound naevus

DO NOT DIAGNOSE IN ADULTS, therefore treat with suspicion.
The differential here will be superficial melanoma or melanoma in situ.

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