Confocal Laser Scanning Microscopy in Dermatology: Manual and Automated Diagnosis of Skin Tumours

The number of melanocytic tumours has increased in the last decades, whereby the frequency of melanoma doubles every 20 years. At present there is a risk of 1:100 to falling sick with a melanoma. According to a WHO report, in the year 2006, about 48,000 melanoma related deaths occur worldwide per year (Lucas et al., 2006). The malignant melanoma is one of the less common types of skin cancer but causes the majority (75%) of skin cancer related deaths. Most melanomas are brown to black looking lesions (Friedman et al., 1985). Warning signs that might indicate a malignant melanoma include change in size, shape and color. Early signs of melanoma are changes to the shape or color of existing moles (ABCD rule). Skin cancer has many potential causes, including: overexposure to UV-radiation (extreme sun exposure during sun-bathing), which may cause skin cancer either via the direct DNA damage or via the indirect DNA damage mechanism; smoking tobacco can double the risk of skin cancer; chronic non-healing wounds; genetic predisposition and the human papilloma virus (HPV), which is often associated with squamous cell carcinoma of the genitals, anus, mouth and fingers (Oliveria et al., 2006) The detection of malignant changes of skin tissue in the early stages will augment the success of the therapy (Marcovic et al., 2009). Metastasis of the melanoma in a progressive stage may spread out to the lymph nodes or even more distant places like: lungs; brain; bone and liver. Such metastatic melanoma may cause general symptoms like: fatigue; vomiting and loss of appetite. The greatest chance of cure is in the early surgical resection of thin melanomas. Therefore, a periodical screening of risk persons is necessary. In the fight against skin cancer, researchers have high hopes in improved and fast provisional screening methods for the clinical routine. Confocal laser scanning microscopy (CLSM) is a novel imaging device enabling the noninvasive examination of skin lesions in real-time (Rajadhyaksha et al., 1999). Therefore, CLSM is very suitable for routine screening and early recognition of skin tumours. The CLSM technique allows the viewing of micro-anatomic structures and individual cells. In contrast to the conventional examination, where suspicious skin tumours have to be excised, embedded in paraffin and stained, this method is much more agreeable for the patient and faster. However, training and experience is necessary for a successful and accurate diagnosis in this new and powerful imaging technique. To diminish the need for training and to improve diagnostic accuracy, computer aided diagnostic systems are required by the derma pathologists.