Porokeratosis

Excerpt

Porokeratosis is an uncommon disorder of keratinization that presents with keratotic papules or annular plaques with an elevated border. The distinct histologic hallmark of porokeratosis is cornoid lamella, a column of tightly fitted parakeratotic cells in the upper epidermis. There are multiple clinical variants of porokeratosis, including:

1. Disseminated superficial actinic porokeratosis

2. Classical porokeratosis of Mibelli

3. Porokeratosis plantaris, palmaris, et disseminate

4. Linear porokeratosis

Additionally, rare variants include:

1. Genitogluteal porokeratosis

2. Facial porokeratosis

3. Giant porokeratosis

4. Porokeratosis ptychotropica

5. Hypertrophic verrucous porokeratosis

6. Eruptive pruritic papular porokeratosis

7. Follicular porokeratosis

8. Reticulate porokeratosis

Variants can occur together but rarely do. Porokeratosis is a precancerous lesion that can undergo malignant transformation. Evaluation of porokeratosis is best conducted with a biopsy of the elevated border. Although multiple therapies exist for porokeratosis (including topical, systemic, and surgical), there are no standard guidelines for treatment.