Custom Search



Pathology of Clear Cell Acanthoma  

"Skin lesion with enlarged pale stained keratinocytes" 

Dr Sampurna Roy MD                  





Clear cell acanthoma (pale cell acanthoma) is a discrete idiopathic psoriasiform lesion of large pale staining, non-keratinizing, glycogenated, monomorphous keratinocytes associated with neutrophils.

The lesion is separated from the adjacent epidermis.

Clinical presentation:  Presents as a firm brown-red dome shaped nodule or papule.

The lesion is usually between 5 to 10 mm or more in diameter. 

It is usually solitary but can be multiple.

Clinical bleeding is rare.

The surface of the lesion may be smooth to bosellated and crusted.

Age:  Middle aged and elderly individuals. Some cases have been reported in younger patients.

Site: Commonly located on the lower limbs. These may also be found on the trunk and face.


Microscopic features:  

Well-demarcated and symmetric lesion elevated in comparison to surrounding skin.

The base of the lesion situated below the rete-ridges of the normal epidermis.

A sharp line can be drawn between the lesional cells and normal epidermis.

There is psoriasiform hyperplasia of the rete ridges with broad base.

The keratinocytes have pale-staining cytoplasm.

A PAS stain with and without diastase confirm the presence of abundant glycogen in the cells.

There is usually no cellular atypia.

Other epidermal changes include mild spongiosis and exocytosis of neutrophils forming small intraepidermal microabscesses.

The epidermal surface shows parakeratotic scales.

Melanocytes within the lesions are variable in number. 

A pigmented variant has been reported.

Papillary dermis is edematous and dermal capillaries are prominent.

An inflammatory infiltrate composed of lymphocytes , plasma cells and rarely eosinophils are present.


Immunohistochemistry:  The cells contain cytokeratin and involucrin but not carcinoembryonic antigen.

Differential diagnosis: Eccrine poroma ; Trichilemmoma ; Psoriasis; Clonal type-Seborrheic keratosis ; Verruca vulgaris  


Further reading:

Clear cell acanthoma with changes of eccrine syringofibroadenoma: reactive change or clue to etiology?

Multiple clear-cell acanthomas.

Clinicopathologic and immunohistochemical studies of conjunctival large cell acanthoma, epidermoid dysplasia, and squamous papilloma.

Clear cell acanthoma of the areola and nipple: clinical, histopathological, and immunohistochemical features of two Brazilian cases.

Clear cell acanthoma.

Clear cell acanthoma induced by a dermatofibroma.

Hemosiderotic clear-cell acanthoma: a pigmented mimicker.

Clear cell acanthoma: a rare clinical diagnosis prior to biopsy.

A case of polypoid clear cell acanthoma on the nipple.

Clear (pale) cell acanthosis as an incidental finding.

A case of polypoid clear cell acanthoma on the scrotum.

Polypoid clear cell acanthoma of the scalp.

Clear cell acanthoma presenting as polypoid papule combined with melanocytic nevus.




Dr Sampurna Roy  MD

Consultant  Histopathologist (Kolkata - India)






Infectious Disease Online


Pathology Quiz Online 


Paediatric Pathology Online


Pancreatic Pathology Online




Endocrine Pathology Online


Eye Pathology Online


Ear Pathology Online


Cardiac Path Online


Pulmonary Pathology Online


Lung Tumour Online




Nutritional Pathology Online


Environmental Pathology Online


Soft Tissue Tumour Online


GI Path Online-India


Gallbladder Pathology Online


E-book - History of Medicine  


Microscope - Seeing the Unseen




Privacy Policy  

Advertising Policy

Copyright 2019