The same criteria found in classic squamous cell carcinoma are present:

• Pleomorphism (cells of varying sizes)
• Nuclear atypia (mitosis with open chromatin)
• Dyskeratotic cells
• Loss of orderly maturation (during the transition from the basal layer to the stratum corneum, cells typically become progressively larger, more elongated, with increasingly eosinophilic cytoplasm; in neoplasia, this expected maturation process is disrupted)
• Dermal infiltration

Presence of acantholysis characterizes the acantholytic variant

Acantholysis

LEGEND

Pleomorphism (cells of varying sizes)

Nuclear atypia (mitosis with open chromatin)

Loss of orderly maturation

Dermal infiltration