Malignant Transformation of Linear Porokeratosis

Porokeratosis (PK) is a rare disorder characterised by clonal expansion of keratinocytes without neoplastic transformation. However, malignant transformation, particularly to squamous cell carcinoma (SCC), is a documented complication. This case report describes a 58-year-old female with a 10-year history of progressively worsening, linear plaques on her left lower extremity. Skin biopsies initially suggested PK, leading to treatment with acitretin and cyclosporine. Subsequent biopsies revealed a moderately differentiating keratinising type of SCC arising within a background of linear PK. The patient ultimately underwent surgical excision and radiation therapy. This case highlights the potential for malignant transformation in PK, particularly the linear subtype. We review the literature on PK subtypes, risk factors for malignancy and management strategies. This case report emphasises the importance of clinical vigilance for malignant transformation in PK, particularly the linear variant. Early diagnosis and appropriate management are crucial for optimal patient outcomes.