Co-existence of Two Types of Porokeratosis with Malignant Transformation / 대한피부과학회지

ABSTRACT

The rate of malignant transformation in porokeratosis (PK) lesions is approximately 7.5%, and linear PK demonstrates the highest rate of malignancy. An 83-year-old woman presented with a rapidly enlarging mass on her left arm. Variably sized erythematous scaly patches were scattered across the left half of her trunk and arm. Additionally, generalized variably sized brownish annular patches with a hyperkeratotic outer ring were observed on her face, trunk and bilateral arms. A skin biopsy was performed on 3 lesions-a yellowish to erythematous appearing mass, an erythematous scaly patch, and a brownish annular patch. Histopathological evaluation of these 3 lesions revealed squamous cell carcinoma, actinic keratosis, and PK, respectively. The final diagnosis was disseminated superficial PK with linear PK on the left side of the body, and actinic keratosis and squamous cell carcinoma confined to the linear PK lesions. We report a case which represents the progressive and stepwise malignant transformation of PK into squamous cell carcinoma.