Porokeratosis of Mibelli

Diagnosis: Porokeratosis of Mibelli

Slightly atrophic patches surrounded by an elevated, warty border (erythema and crusted erosions on some lesions are post cryotherapy)

Clinical Presentation

Slightly atrophic patches surrounded by an elevated, warty border (erythema and crusted erosions on some lesions are post cryotherapy)

Clinical History

Submitted by Alaa Saad. Originally posted January 18, 2011.

Treatment

See case discussion.

Differential Diagnosis

• Actinic keratosis • Psoriasis • Tinea corporis • Granuloma annulare • Bowen disease • Lichen planus

Key Learnings

• Disorder of keratinization with characteristic cornoid lamella (column of parakeratotic cells) • Classic: annular plaque with raised, thread-like peripheral ridge • Subtypes: classic of Mibelli, disseminated superficial actinic (DSAP), linear, punctate, palmoplantar • DSAP is the most common variant — multiple small lesions on sun-exposed areas • Malignant transformation to SCC/BCC occurs in ~7-10% of long-standing lesions • Immunosuppression exacerbates disease and increases malignancy risk

Tags: porokeratosis, mibelli, alaa saad