Case Report: Marjolin ulcer characterized by squamous cell carcinoma arising from chronic wounds: clinical features, diagnostic and therapeutic challenges, and insights—a report of four cases

Purpose This study aimed to analyze the clinical features and diagnostic challenges of cutaneous squamous cell carcinoma arising from chronic limb wounds—a condition known as a Marjolin ulcer—to summarize practical warning signals for early recognition and to explore the underlying mechanism of malignant transformation associated with chronic inflammation. Methods We present a detailed report of four elderly male patients. All of them had long-standing, non-healing chronic wounds on the limbs, with initial triggers including an ingrown nail, a foreign body injury, a post-surgical scar from a calcaneal fracture, and an abrasion. The wound duration ranged from 8 months to 30 years. Clinical presentations, imaging findings, surgical procedures, pathological results, and short-term postoperative outcomes were systematically reviewed. Results All patients were initially misdiagnosed with benign chronic wounds, leading to diagnostic delays from months to decades. Final surgical pathology confirmed cutaneous squamous cell carcinoma in every case, with bone invasion present in two cases. Owing to these delays, treatment escalated from potentially curative local excision to amputation in three of the four cases. No local recurrence was detected during the short-term follow-up period. Conclusion Based on these cases, we propose a practical set of clinical warning signals centered on wound chronicity, abnormal morphology, and patient demographics. Long-standing, non-healing wounds on the limbs of elderly male patients should prompt suspicion of malignant transformation. Early biopsy is essential to avoid devastating outcomes such as amputation. The chronic inflammatory microenvironment appears to serve as a continuous driving force behind this cancer development pathway.