Francesca Cheung, MD CCFP, is a family physician with a special interest in dermatology. She received the Diploma in Practical Dermatology from the Department of Dermatology at Cardiff University in Wales, UK. She is practising at the Lynde Centre for Dermatology in Markham, Ontario and works closely with Dr. Charles Lynde, MD FRCPC, an experienced dermatologist. In addition to providing direct patient care, she acts as a sub-investigator in multiple clinical studies involving psoriasis, onychomycosis, and acne.

Abstract
Basal cell carcinoma (BCC) is a type of non-melanoma skin cancer that arises from basal cells found in the lower layer of the epidermis. It is the most common type of skin cancer in humans, but they rarely metastasize. If BCC is left untreated and progresses, it may lead to significant morbidity and cosmetic disgurement. In nearly all cases, the recommended treatment modality for BCC is surgery. Small and superficial BCC may respond to local immune-modulating therapies. For tumors that are more difficult to treat or those in which tissue preservation is essential, Mohs micrographic surgery should be considered. Radiation therapy can be used for advanced and extended BCC and in those patients for whom surgery is contraindicated. Photodynamic therapy is usually used as an adjunct in BCCs with poorly defined border, in cases which oculoplastic surgery will be extensive or difficult, or in recurrent BCCs with tissue atrophy or scar formation. Oral vismodegib has been approved for the treatment of adult patients with locally advanced basal cell carcinoma who are not candidates for surgery or radiation and for those with metastatic disease. The prognosis for BCC is generally great with 100% survival rate for localized cases.
Keywords: Basal cell carcinoma, Nonmelanoma skin cancer, Hedgehog intracellular signalling pathway, Imiquimod 5% cream, 5-Fluorouracil 5% cream.

Erin Dahlke, MD, Dermatology Resident, University of Toronto, Toronto, ON.
Christian A. Murray, MD, FRCPC, Assistant Professor of Medicine and Dermatology, University of Toronto; Co-director of Dermatologic Surgery, Women’s College Hospital, Toronto, ON.

Basal cell carcinoma (BCC) is a common, slow-growing malignant skin tumour that only very rarely metastasizes. The main subtypes of BCC are nodular, superficial, and sclerosing. The most important risk factors for the development of BCC include fair skin, extensive sun exposure as a child, past personal history of skin cancer, and advanced age. Basal cell carcinoma is the most common human malignancy, and its incidence is increasing worldwide. There are a number of different treatm ent modalities for BCC including topical therapies, cryotherapy, electrodesiccation and curettage, surgical excision, radiotherapy, and Mohs’ micrographic surgery. Treatment should be tailored to the individual situation, and advanced age does not typically alter the management choice or reduce the expectation of an excellent outcome, including cure.
Key words: basal cell carcinoma, nonmelanoma skin cancer, risk factors, epidemiology, treatment.

John Kraft, HBSc, Medical Student, University of Toronto, ON.
Carrie Lynde, HBSc, Medical Student, University of Toronto, ON.
Charles Lynde, MD, FRCPC, Assistant Professor, Dermatology, University of Toronto, Toronto; Dermatology Consultant for Metropolitan Homes for the Aged in Toronto, Markham-Stouffville Hospital, and Scarborough Grace Hospital; Dermatologist, Dermatology Practice, Markham; Former President, Canadian Dermatology Association.

Skin neoplasias are more commonly seen in older patients. These skin diseases can frequently be more severe, particularly in long-term care residents. Common nonmelanoma skin cancers seen in these individuals include actinic keratoses, squamous cell carcinomas, and basal cell carcinomas. Benign neoplasias that are seen in older patients include seborrheic keratoses, skin tags, and classical Kaposi’s sarcoma. Treatment for neoplasias in the older adult are often not as aggressive as in younger patients.
Key words: actinic keratosis, squamous cell carcinoma, basal cell carcinoma, seborrheic keratosis, skin tag, classical Kaposi’s sarcoma.

John E. Adam MD, FRCPC, Professor of Medicine (Dermatology), University of Ottawa, Ottawa, ON.

The annual number of new cases of skin cancers reported in Canada is estimated to be about 40,000. With the aging of the baby boomer generation, this figure is anticipated to increase because of the ease of travel to the south in winter and increased exposure to the sun during outdoor activities. Dermatoheliosis or photodamage is most prevalent in people over 40 years of age who have had excessive sun exposure over their lifetime (Table 1). Epidemiological studies have identified sunlight exposure as the major risk factor for skin cancer.

There are three major types of skin cancer. The most common non-melanocytic skin cancers are Basal Cell Carcinoma and Squamous Cell Carcinoma. The less frequently occurring melanocytic skin cancer is Malignant Melanoma.

Basal cell carcinoma
Basal Cell Carcinoma (BCC) is the most common form of skin cancer but also the least likely to metastasize. It can be very destructive locally if not diagnosed and treated early.

Clinically it presents in several forms on sun-exposed areas (Table 2). The classic and most common presentation is the nodulo-cystic variety--a shiny elevated dome shaped nodule with a raised border often with telangiectatic blood vessels on the surface. The tumour is described as shiny or of a "mother-of-pearl colour.