Related Experiment Video
Updated: Aug 14, 2026

Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
Published on: September 7, 2013
Melanocyte halo explained
Abstract:
Electron microscopic examination was performed of skin biopsy specimens processed for electron microscopy directly after formaldehyde fixation, after retrieval from paraffin blocks, and as for paraffin embedding but with retrieval after clearing with xylene, the last step before paraffin infiltration. The halos surrounding melanocytes in the epidermis are a retraction artifact that develops during paraffin infiltration of the tissue. It is proposed that this artifact is related to the high temperature of the paraffin bath.
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