Hematoporphyrin injection mediated photodynamic therapy for secondary squamous cell carcinoma of arsenical keratosis: A case report

•Arsenical keratosis frequently coexists with skin neoplasms, with the most prevalent ones being Bowen's disease, basal cell carcinoma, squamous cell carcinoma, and extramammary Paget's disease.•Photodynamic therapy with hematoporphyrin injection is a significant optional treatment for secondary squamous cell carcinoma associated with arsenical keratosis, and it is deserving of clinical implementation. Hematoporphyrin injection (HpD) mediated photodynamic therapy (PDT) has demonstrated efficacy in treating various types of Bowen's disease, including basal-cell carcinoma, squamous cell carcinoma, extramammary Paget's disease, and actinic keratosis. We present a case of a male patient who developed squamous cell carcinoma as a result of repeated instances of arsenic-induced keratosis on both his hands and feet. Due to the involvement of the joint in both hands, the patient declined the conventional surgical resection treatment since it could potentially impact normal physiological function. Instead, the patient chose to undergo hemoporphyrin photodynamic therapy. After the treatment, the rash was entirely eliminated and there were no restrictions in the movement of the joint. Nevertheless, a local recurrence was detected throughout the two-year monitoring period. Arsenical keratosis carries a substantial likelihood of recurring. However, we believe that hemoporphyrin photodynamic therapy is effective in treating this condition.