Clear Cell Papulosis
Christine J. Ko, MD
Key Facts
Terminology
Rare disorder
Multiple, hypopigmented to white, flat-topped papules and macules
Generally on lower trunk/suprapubic area
Almost always in young children
More common in Asian populations
Microscopic Pathology
Clear to pale cells with abundant cytoplasm
Cells concentrated in basal layers of epidermis
Cells single or in clusters
Nuclear atypia and pleomorphism absent
Cells positive with CK7
Top Differential Diagnoses
Clear cells of Toker
Pagetoid dyskeratosis
Paget disease
Extramammary Paget disease
 Symmetrically distributed hypopigmented macules and papules are seen on the abdomen and suprapubic region of a young child. (Courtesy R. Hui, MD.) |
 Clear/pale cells  are seen with abundant cytoplasm in the basal and suprabasal layers of a hyperkeratotic and acanthotic epidermis. (Courtesy R. Hui, MD.) |
TERMINOLOGY
Definitions
Rare disorder of multiple, hypopigmented to white, flat-topped papules and macules
Generally on lower trunk
Almost always in young children, often of Asian descent
Histopathology characteristic, with clear/pale cells in basal layer of acanthotic epidermis
ETIOLOGY/PATHOGENESIS
Pathogenesis
Clear cells may be normal component of epidermis along “milk lines,” type of glandular epithelial cell
Others postulate that clear cells are derived from eccrine secretory gland
Based on staining of clear cells with IKH-4, carcinoembryonic antigen, and CAM5.2
Genetic component is postulated as siblings may be affected
CLINICAL ISSUES
