Clinicopathological evaluation of nonmelanoma skin cancer.

BACKGROUND: Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), in combination, are referred to as nonmelanoma skin cancers (NMSCs). NMSC is not as extensively studied in the Asian population as it is in the Caucasian population. AIM: This study sought to evaluate the clinical and histopathologic aspects of NMSC from cases of cutaneous malignancies.
MATERIALS AND METHODS: The present study is a descriptive analysis of NMSC specimens seen at Department of Pathology, SSIMS and RC, Davangere. Histologically diagnosed NMSC, i.e. BCC and SCC specimens from January 2005 to December 2009 were analyzed according to site distribution, risk factors and histological variants.
RESULTS: Of the various specimens received during the 5year study period, 60 were histologically categorized as skin malignancies, of which 31(51.6%) cases were of NMSC. SCC was the most common NMSC constituting 26 (83.9%) cases and 5 NMSC cases (16.1%) were of BCC. The most common incidence was among the age group 60-80 years (80%) for BCC and 40-60 years (50%) for SCC. Head and neck was the most common site of presentation with predilection for face. Forty-six percent of SCC was histologically categorized as well differentiated, 42.3% as moderately differentiated and 11.5% as poorly differentiated. Most common histological variant of BCC was solid (nodular) type.
CONCLUSION: NMSC often associated with greater morbidity, necessitating increased efforts to assess risk factors in individuals, to encourage periodic self-examination and professional evaluation of skin and to optimize strategies for earlier diagnosis and treatment.

Introduction

Skin is the largest organ in human body. But skin cancers are relatively uncommon malignancies worldwide. Three most frequent primary skin cancers are basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma. BCC and SCC, in combination, are referred to as nonmelanoma skin cancers (NMSCs).[1] NMSC is not usually life threatening unlike malignant melanoma, but morbidity is a main concern.[2] In India, the incidence of skin malignancies is low, constituting about 1-2% of all the diagnosed cancers. BCC is the commonest skin cancer worldwide, but various studies from India have reported SCC as the most prevalent skin malignancy.[3]

SCC commonly occurs on sun-damaged skin in white populations.[4] Risk factors for the development of SCC in darkly pigmented individuals are chronic scarring and areas of chronic inflammation. It is the most frequent type of malignant tumor arising in scarred skin.[5] These risk factors have been associated with a greater potential for metastasis. Development of BCC has been correlated with prolonged, intensive UV exposure, with BCC occurring most commonly after the fifth decade of life. More than 90% of BCC develop in sun-exposed areas of the head and neck region regardless of the degree of pigmentation in an individual.[4]

Since skin cancers are usually visible, most of them can be diagnosed early and treated with minimal cost and facilities. The present study sought to evaluate the clinical and histopathologic aspects of NMSC from cases of cutaneous malignancies.

Materials and Methods

The present study was conducted in a tertiary care teaching hospital which mainly caters to the nearby village population. Main focus of the study was to understand the pathology of nonmelanoma cancer in the sun-exposed area, thereby excluding the malignancies of anogenital region.

A retrospective analysis of skin biopsies and specimens received at the Department of Pathology from 2005 to 2009 was performed. Gross examination findings were noted. Tissue sections were studied by routine hematoxylin and eosin staining. Final diagnosis was given considering the clinical history, gross and histopathology.

Of the 60 histologically confirmed skin malignancies during the 5-year study period, 31 (51.6%) were categorized as NMSC. The variables evaluated included site distribution, risk factors and histological variants of NMSC.

Results

Of the various specimens received during the 5-year study period, 60 were histologically categorized as skin malignancies, of which 31 (51.6%) cases were of NMSC. SCC was the most common NMSC, constituting 26 (83.9%) cases, and BCC constituted 5 (13.1%) cases. Twenty-three cases (74.2%) were males and 8 cases (25.8%) females, with a male to female ratio of 1:0.35.

Age of the patients ranged from 20 to 80 years with mean age of 52.8 years. The most common incidence was among the age group 60-80 years (80%) for BCC and 40-60 years (50%) for SCC. Tumors were rare below the age of 20 years, with only one case in the present study [Table 1].

Table 1

Age/sex distribution of NMSC

Distribution of primary sites involved is shown in [Table 2]. Most cases of SCC (50%) were seen in the head and neck region, with majority in face including lip. Increased number of SCC (38.4%) cases were also seen in lower limb, especially involving the foot. Majority of the BCC cases, i.e. 80%, were reported in the head and neck region with predilection for face.

Table 2

Distribution of primary sites involved

Majority of NMSCs (61.2%) clinically presented as ulcerative lesion. For BCC, except for a biopsy the rest of the four specimens received were widely excised tissue. For SCC, most were 12 (46.2%) specimens of wide excision, 9 (34.6%) were biopsy from the lesion, 3 (11.5%) were amputated limbs (1 above elbow and 2 above knee amputation) and 2 (7.7%) were review slides for second opinion.

Forty-six percent of SCC was histologically categorized as well differentiated, 42.3% as moderately differentiated and 11.5% as poorly differentiated. One case of poorly differentiated SCC also presented with regional lymph node metastasis. For BCC, the most common histological variant was solid (nodular) type with four cases and keratotic type in one case.

Discussion

BCC and SCC, in combination, are referred to as NMSCs.[1] BCC is the commonest skin cancer worldwide, but various studies from India have reported SCC as the most prevalent skin malignancy.[3] In the present series, nearly 74% of all reported cases of NMSC relate to the fourth and later decades. The frequency of NMSC in men and women is different. Present study shows male preponderance comparable to other studies.[67]

NMSC occurs mainly in the sun-exposed regions predominantly involving face and neck areas of the body.[8] The present study shows that 54% of the reported NMSCs were found in the head and neck region, which demonstrates the major influence of sun exposure in the development of skin cancers.

SCC was the commonest NMSC in the present series similar to that reported in other studies.[68] SCC commonly occurs on sun- damaged skin. Our results indicate that SCC (50%) affects body locations which are usually sun exposed, such as the face, scalp and upper arm. This corroborates the result of a previous study by Franceschi et al.[8]

Risk factors for the development of SCC in darkly pigmented individuals are chronic scarring and areas of chronic inflammation. These risk factors have been associated with a greater potential for metastasis.[4] In the present study, 38.4% of cases were seen in non sun-exposed sites, involving the lower limb with predilection for foot. Of the two above knee-amputated specimens, one of the cases presented with regional lymph node metastasis.

SCC is the most frequent type of malignant tumor arising in scarred skin.[79] Overall prognosis of scar SCC is less favorable compared to non-scar SCC.[10] Two cases of SCC in the present study were seen in old burnt scar. The most common histopathologic pattern of SCC was the well differentiated form constituting 46.2% comparable to the report of a study by Alakloby et al.[7]

Development of BCC has been correlated with prolonged, intensive UV exposure, with BCC occurring most commonly after the fifth decade of life.[4] More than 90% of BCCs develop in sun-exposed areas of the head and neck region regardless of the degree of pigmentation in an individual.[4] BCC constituted smaller portion (16.1%) of NMSC in the present study in contrast to other studies.[711] BCC in this series predominantly (80%) involved the face comparable to other studies[4] and showed high incidence rate over sixth decade. Rare BCC sites include nipple, penis, anus, groin, popliteal fossae, ankle, and scalp.[4] The present study also showed a case of BCC involving the foot. The most common histopathologic pattern was the solid (nodular) pattern, which was also reported by Alakloby et al.[7]

Our results emphasize, SCC as the most common nonmelanoma cancer and if it occurs on non sun-exposed regions like foot is associated with increased morbidity, possibly due to advanced disease stage at the time of diagnosis.

Conclusions

NMSCs are often associated with greater morbidity, necessitating increased efforts to assess risk factors in individuals, to encourage periodic self-examination and professional evaluation of skin and to optimize strategies for earlier diagnosis and treatment.