TABLE 1.

Criteria used for distinguishing melanocytes and keratinocytes by transmission electron microscopy

Feature	Melanocytes	Keratinocytes
Cytoskeletal features	Not clearly observed	Bundles of actin/keratin fibrils often visible
Desmosomes	Absent between melanocytes and keratinocytes	Present between adjacent keratinocytes, predominantly in stratum spinosum
Electron density	Relatively electron‐dense cytoplasm	Relatively electron‐lucent cytoplasm, especially in apical layers
Glycogen granules	Few cytoplasmic glycogen granules	Many cytoplasmic glycogen granules
Melanin content	Densely packed with melanosomes	Sparsely packed with melanokerasomes (MKS)
Position	Cell body in the basal layer only	In all the stratified layers
Shape	Usually visible as small cylindrical dendrites, except when cell body is observed in stratum basale	Large, flat cells often with flattened nucleus

Features used to correctly identify melanocytes and keratinocytes by TEM are listed.