Clear Cell Acanthoma
Christine J. Ko, MD
Key Facts
Clinical Issues
Common in middle-aged women
Generally on lower legs
Solitary, pink-red, shiny papule or plaque
Microscopic Pathology
Acanthosis of pale or clear cells
Often overlying parakeratosis, sometimes with neutrophils
Pale or clear cells (glycogen filled, PAS[+]) sharply demarcated from adjacent, normal epidermis
Minimal to no cytologic atypia
Top Differential Diagnoses
Psoriasis
Psoriasiform keratosis
Tricholemmoma
Clear cell Bowen disease
 Clear cell acanthoma at low-power magnification shows clear/pale cells in an acanthotic epidermis. The lesion is sharply demarcated from the surrounding epidermis  . |
 In this medium-power magnification of clear cell acanthoma, there are clear/pale cells  with overlying parakeratosis. The lesion is sharply demarcated from the adjacent normal epidermis  . |
TERMINOLOGY
Abbreviations
Clear cell acanthoma (CCA)
Synonyms
Degos acanthoma, pale cell acanthoma
Definitions
Benign epidermal tumor, generally on lower legs of women
Epidermal acanthosis with pale or clear cells, often with overlying parakeratosis
Pale or clear cells sharply demarcated from adjacent, normal epidermis
ETIOLOGY/PATHOGENESIS
