MELANOMA AND SQUAMOUS CELL CARCINOMA DEVELOPING ON A BURN SCAR

Introduction. Development of malignancy in chronic burn scars is described in 2% of cases, with cutaneous squamous cell carcinoma (cSCC) being the most frequent. It develops several years after the burn injury, as a consequence of malignant transformation in chronically inflamed tissue. Melanoma in a burn scar is, however, quite rare; in several cases, a synchronous or metachronous appearance of melanoma and cutaneous squamous cell carcinoma was noted. Based on the previous rare reports, melanoma and cSCC can concurrently arise on thermal burn scars, as well as on the areas treated with skin grafts. Case report. We report on a case of a 67-year-old male who was accidentally scalded by boiling water at the age of 14. The patient subsequently developed melanoma at the age of 60, accordint to clinical and dermoscopic examination at the site of the burn scar, and after excision and histopathological analysis, the diagnosis of melanoma was confirmed (superficial spreading melanoma, Breslow 0.87 mm, with ulceration, pT1b). Complete surgical excision was done and diagnosis confirmed on histopathological analysis. After diagnosis of melanoma, regular follow-up every six months was schedule, and three years after, cSCC was suspected and confirmed after surgical excision and histopathologic analysis. Conclusion. This case highlights the importance of long-term dermatological follow-up after burn injuries and early detection and treatment of skin cancer that can lead to better outcome in this group of patients.


Abstract
Introduction. Development of malignancy in chronic burn scars is described in 2% of cases, with cutaneous squamous cell carcinoma (cSCC) being the most frequent. It develops several years after the burn injury, as a consequence of malignant transformation in chronically inflamed tissue. Melanoma in a burn scar is, however, quite rare; in several cases, a synchronous or metachronous appearance of melanoma and cutaneous squamous cell carcinoma was noted. Based on the previous rare reports, melanoma and cSCC can concurrently arise on thermal burn scars, as well as on the areas treated with skin grafts.
Case report. We report on a case of a 67-year-old male who was accidentally scalded by boiling water at the age of 14. The patient subsequently developed melanoma at the age of 60, accordint to clinical and dermoscopic examination at the site of the burn scar, and after excision and histopathological analysis, the diagnosis of melanoma was confirmed (superficial spreading melanoma, Breslow 0.87 mm, with ulceration, pT1b). Complete surgical excision was done and diagnosis confirmed on histopathological analysis. After diagnosis of melanoma, regular follow-up every six months was schedule, and three years after, cSCC was suspected and confirmed after surgical excision and histopathologic analysis. Conclusion. This case highlights the importance of long-term dermatological follow-up after burn injuries and early detection and treatment of skin cancer that can lead to better outcome in this group of patients.

Introduction
About 2% of chronic burn scars develop into malignant tumors many years after the burn occurrence 1 . Squamous cell carcinoma is the most frequent cancer that arises on the affected skin 2 , although in a general population, this form of malignant tumor is less common than basal cell carcinoma. Available empirical evidence suggests a mean time latency of 23 to 37 years 3 . However, not many cases of melanoma on thermal burn scars are reported in pertinent literature 1, 2, 4-7 . They nonetheless suggest that melanoma (MM) and squamous cell carcinoma (SCC) can concurrently arise on thermal burn scars, as well as on the areas treated with skin grafts 2, 6 .

Case report
We report on a case of a 67-year-old male who suffered burns after being accidentally

Discussion
There are few epidemiological data available on the risk of skin cancer arising in scars, but is described to occur in 2% of patients. Wallingford's review has identified a major gap in scientific knowledge regarding the incidence of scar neoplasms, despite a significant number of case reports 8 . Although burn patients are not at higher risk of developing skin cancers in general, a modest increase in the prevalence of SCC at sites of past burn injuries cannot be excluded, nor can excess risk in longer study follow-up periods be disregarded 8 . The development of melanoma on a burn scar is relatively rare; in several cases, a synchronous or metachronous appearance of melanoma and cutaneous squamous cell carcinoma was reported 2,11,12 . In one report, multiple melanoma developed at the site of a burn scar, and in another, rare desoplastic melanoma with regional lymph node metastases was described 13,14 .
In a largest review, 23 cases of melanoma and 5 cases with concomitant presence of cutaneous squamous cell carcinoma and melanoma were described, and in majority of patients skin cancer developed after a long period from the age of burn occurrence to the melanoma diagnosis (41 ± 26 years in the 23 malignant melanoma only cases, and 48 ± 13 years in the 5 cases involving both squamous cell carcinoma and malignant melanoma) 8 .
Also, in another report an average latency time from burn to melanoma diagnosis was 45 years 1 . Our patient developed melanoma 46 years after burn injury, which was followed by diagnosis of cutaneous squamous cell carcinoma three years later. A very long latency period was reported by Uchida et al., who described a case of a 78-year-old Japanese female with malignant melanoma that developed on a thermal burn scar after more than 70 years 7 . This suggests the need for a long-term dermatological follow-up of all burn patients.
The mortality rate associated with cutaneous SCC is about 1% 15 , while in skin cancers developing in a scar it can be as high as 21-38% based on previous literature, median survival after scar cancer diagnosis was reported to be 25 months, while 5-year survival rate varies from 52% to 80% 2 . In patients with involvement of regional lymph nodes, median survival was 16 months, increasing to 66 months for those without lymph node metastases 3 . Our patient is on regular follow-ups and is disease-free during the six-year follow-up.
Self-skin examination and regular clinical and dermoscopic follow-up should be recommended to patients with burn injuries, for an early diagnosis of skin cancer to avoid the complications and poor outcome in advanced disease. Initial early grafting for a deep burn wound and proper scar care is also advised 16 .

Conclusion
Periodical and very long follow-up of thermal burn scars is important for early diagnosis of malignant transformation and timely and adequate treatment, in order to improve the outcome in these patients.