We performed multiphoton fluorescence (MF) and second-harmonic generation (SHG) imaging on human basal cell carcinoma samples. In the dermis, basal cell carcinomas can be identified by masses of autofluorescent cells with relatively large nuclei and marked peripheral palisading. In the normal dermis, SHG from dermal collagen contributes largely to the multiphoton signal. However, within the cancer stroma, SHG signals diminish and are replaced by autofluorescent signals, indicating that normal collagen structures responsible for SHG have been altered. To better delineate the cancer cells and cancer stroma from the normal dermis, a quantitative MF to SHG index is developed. We demonstrate that this index can be used to differentiate cancer cells and adjacent cancer stroma from the normal dermis. Our work shows that MF and SHG imaging can be an alternative for Mohs’ surgery in the real-time guidance of the secure removal of basal cell carcinoma.

Higher harmonic generation microscopy (HHGM), combining both second- and third-harmonic generation (SHG and THG) modalities, is a new paradigm for in vivo noninvasive virtual biopsy. With the ability to achieve noninvasiveness, high resolution, and high penetrability at the same time, HHGM is a promising tool for future noninvasive diagnosis of skin diseases. In this paper, we report our preliminary pilot clinical trial results on in vivo virtual biopsy of human skin by using HHGM. In vivo virtual biopsy imaging has been performed on 21 volunteers' inside and outside forearm skin along with the damage evaluation. Together with an embryo viability study, our results not only indicate a superior viability performance of the developed system, but also a much improved penetrability in different skin types. Ex vivo studies further confirm the capability of the developed virtual biopsy system to pathohistologically distinguish different skin diseases. Our in vivo HHGM biopsy study of human skin with different colors also reveals the central role of melanin in the epi-THG resonance enhancement and attenuation. With a unique capability to molecular image the melanin distribution, epi-THG microscopy is also highly valuable for diagnosing and screening early melanocytic lesions.

Background: Geriatric health care has become a worldwide concern, but relatively few statistical studies are available about geriatric skin diseases. Moreover, no information exists regarding skin disorders among the elderly population in Taiwan that has become a geriatric country. Objective: To determine the characteristic pattern and the prevalence of various skin disorders for the elderly who visited the National Taiwan University in the last 7 years. Methods: Using a database from the Dermatology Outpatient Clinic of the National Taiwan University Hospital, 1993–1999 file, we conducted a retrospective cross-sectional study by evaluating the age, proportion, and gender of each specific cutaneous disease category, χ² tests were used for analyzing statistical significance. The analysis supplied odds ratios and 95% confidence intervals. Results: A total of 16,924 patients aged 65 years and older, which constituted 11% of the total patients seen at the Clinic of Dermatology from 1993 through 1999, were studied. The male to female ratio was 1.3 to 1. The most common cutaneous disorder in the elderly was dermatitis (58.7%), followed by fungal infections (38.0%), pruritus (14.2%), benign tumors (12.8%), and viral infections (12.3%). Cutaneous malignant tumors were found in 2.1%. Basal cell carcinoma occurred in 29.8%, actinic keratosis in 22.4%, Bowen’s disease in 13.3% and squamous cell carcinoma 13.3%. Interestingly, our cases of extramammary Paget’s disease showed a male predominance. Most melanomas were acral lentiginous melanoma located on the soles. The prevalence of common diseases in elderly patients compared with those outpatients of less than 65 years showed a 3-fold increased risk for pruritus. Moreover, the pattern of geriatric skin diseases in Taiwan was significantly different from Western countries. Conclusion: The prevalence of skin diseases in elderly patients emphasizes the importance of health education in geriatric people in Taiwan concerning appropriate use of emollients, proper foot care, sun protection and early detection of skin cancers.