Table of Contents

Clear cell acanthoma

LEGEND

Clear cell acanthoma presents with fairly classic histopathological findings.

This is a tumor that is easy to recognize even at low magnification.

Key characteristics:

  • Psoriasiform hyperplasia

  • Pronounced / well-demarcated borders

  • Clear cells with cytoplasm rich in glycogen (PAS+, Periodic Acid-Schiff positive)

Clear cell acanthoma

LEGEND

  • Psoriasiform hyperplasia

  • Sharp demarcation between clear cells and adjacent normal keratinocytes

  • Crust

Clear cell acanthoma

LEGEND

  • Psoriasiform hyperplasia consists of regular elongation of the rete ridges, thinning of the epidermis above dermal papillae, widening at the base of the rete ridges, resembling golf clubs

  • Fusion of the lower portions of rete ridges
  • Neutrophils often found in the stratum corneum or remaining epidermis
  • Crust

Clear cell acanthoma

LEGEND

Cytoplasm rich in glycogen that stains with PAS (Periodic Acid-Schiff)

  • Sharp transition between clear cells and darker adjacent keratinocytes
  • Intracorneal collections of neutrophils

Clear cell acanthoma

LEGEND

  • Surface crust with neutrophil collection
  • Tortuous and dilated blood vessels
  • Mild perivascular lymphocytic infiltrate