Pathology of Dermatosis Papulosa Nigra

"Benign epithelial lesion noted in coloured population"

Dr Sampurna Roy MD          2022

It is regarded as a variant of seborrheic keratosis by some authors.

However, unlike seborrheic keratosis the proliferating epithelial cells are not composed of basaloid cells.

Clinically, dermatosis papulosa nigra presents as multiple small pedunculated papules less than 5 mm in diameter.

These are predominantly located on the forehead, malar region of the face, neck, and upper trunk.

According to a study of 30 patients the Dermatosis  papulosa nigra was predominantly noted in female patients.

The average age of onset of the lesions was 22 years, with a progressive increase in size and number.

Family predisposition, and photodistribution of the lesions were found.

Microscopic features:

The lesion is characterised by parakeratosis, papillomatosis, acanthosis, hyperpigmentation of the basal layer, thick interwoven tracts of epithelial cells, and horn cysts. 

The horny layer shows basket weave pattern.

Keratin filled invagination of the epidermis is often present.

Melanophages may be present in the dermis.

Further reading

Postprocedural wound-healing efficacy following removal of dermatosis papulosa nigra lesions in an African American population: a comparison of a skin protectant ointment and a topical antibiotic.

Clinical features and treatment of dermatosis papulosa nigra in migrants to Italy.

Treatment of dermatosis papulosa nigra in 10 patients: a comparison trial of electrodesiccation, pulsed dye laser, and curettage.

FGFR3 and PIK3CA mutations in stucco keratosis and dermatosis papulosa nigra.

Comparison of electrodesiccation and potassium-titanyl-phosphate laser for treatment of dermatosis papulosa nigra.

Treatment of dermatosis papulosa nigra with a 1064 nm Nd:YAG laser: report of two cases.

Dermatosis papulosa nigra in Dakar, Senegal.