Predisposing factors and histopathological variants of cutaneous squamous cell carcinoma: Experience from a North Indian teaching hospital

Background: Squamous and basal cell carcinomas together constitute the majority of non-melanoma skin cancers. These malignancies are infrequent in Indians as compared to the white skinned population. Literature on squamous cell carcinoma in dark skin is limited. Aim: To analyze the risk factors and to characterize the histopathological subtypes of cutaneous squamous cell carcinoma in Indian patients in an area, non-endemic for arsenicosis. Methods: A retrospective analysis of data from January 2003 to August 2013 was performed to evaluate the predisposing factors and histopathological types of cutaneous squamous cell carcinoma at the Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh. Demographic and disease characteristics such as age, gender and predisposing factors, particularly premalignant dermatoses were recorded and histopathology slides were reviewed. Results: Of the 13,426 skin biopsy specimens received during the 10-year period, there were 82 (0.6%) cases of squamous cell carcinoma and 170 (1.7%) of basal cell carcinoma. The mean age at diagnosis of cutaneous squamous cell carcinoma was 53.7 years and the male to female ratio was 2:1. The most common site of involvement was the lower limbs in 34 (41.5%) patients. Marjolin's ulcer was present in 36 (43.9%) cases. No predisposing factor was identified in 35 (42.7%) patients. Histopathologically, the tumors were classified most commonly as squamous cell carcinoma not otherwise specified in 33 (40.2%) cases. Limitations: This was a retrospective study and details of occupation and interval between the precursor lesions and development of tumor were not recorded. Immunohistochemistry for human papilloma virus and p53 tumor suppressor protein were not performed as these tests were not available. Conclusion: Cutaneous squamous cell carcinoma is uncommon in Indian patients and a high index of suspicion is necessary when a rapidly enlarging nodule, verrucous fungating plaque or an ulcer with everted margins develops in long standing scars and other predisposing dermatologic conditions. Histopathological examination is mandatory to confirm the diagnosis and identify the subtype and this has prognostic implications.