In-vivo Evaluation von Hauttumoren und inflammatorischen Dermatosen mittels nicht invasiver Bildgebung

Gust, Charlotte (2024): In-vivo Evaluation von Hauttumoren und inflammatorischen Dermatosen mittels nicht invasiver Bildgebung = In-vivo evaluation of skin tumors and inflammatory dermatoses with non-invasive imaging modalities. Dissertation, LMU München: Medizinische Fakultät

Abstract

This cumulative dissertation focusses on various applications of non-invasive imaging modalities in Dermatology. It aims to contribute to a better understanding of different non-invasive diagnostic methods and demonstrates their various applications. In addition to already established methods such as Dermoscopy, optical coherence tomography (OCT) and reflectance confocal microscopy (RCM), this work particularly addresses the new imaging method LC-OCT. This relatively unexplored technique has been applied in the early diagnosis of precancerous skin lesions and skin tumors with the intention of establishing diagnostic criteria. These were compared to correlates of already known OCT, RCM and histology criteria and tested for applicability in cases of dermatoscopically unclear lesions. When suspicion of a skin disease arises after clinical inspection and Dermoscopy, a tissue sample is taken to confirm diagnosis. This approach is costly, time-consuming and not always conclusive, especially in larger or multilocular lesions. Conventional histology is the gold standard for diagnosing skin tumors and many other skin diseases. Efforts are being made to find methods that provide comparable diagnostic accuracy whilst being more cost-effective and timesaving than histological examination. In the context of this research project, images of skin tumors were taken using the LC-OCT technique and compared with corresponding H&E sections. Characteristic features for the respective skin diseases were identified and compared to already known features from OCT and RCM. LC-OCT showed higher diagnostic confidence in the diagnosis and subtyping of BCC compared to other techniques. When considering lesions clinically not confidently classifiable as BCC but suspicious for BCC, very good diagnostic confidence and performance were achieved with LC- OCT to distinguish these lesions, compared to Dermoscopy and histology as the gold standard. Pitfalls, lesions misdiagnosed as BCC, occurred in 14 out of 182 lesions and consisted of sebaceous hyperplasia, molluscum contagiosum, pyogenic granuloma and actinic keratosis. Nevertheless, LC-OCT can assist clinicians in the diagnosis and subtyping of BCC and optimize both the diagnostic approach and the treatment procedure. In addition to avoiding unnecessary skin biopsies, this would have implications for therapy as well. While nodular and fibrosing BCCs should be treated surgically, conservative therapy options can be considered for superficial BCC. Expanding the application spectrum of LC-OCT to other keratinocytic tumors, such as squamous cell carcinoma or its precursor actinic keratosis, showed new possibilities for the classification of field cancerization. By analyzing keratinocyte morphology and the architecture of the dermoepidermal junction, various stages of keratinocytic carcinomas can reliably be distinguished and correlated histologically. Furthermore, LC-OCT was able to classify actinic keratoses based on the basal growth pattern of keratinocytes, providing the possibility to depict the PRO classification in vivo. The classification estimates the malignant transformation potential of AK by the displacement of keratinocytes into the papillary dermis, which could be achieved noninvasively with LC-OCT in the future. Examining melanocytic lesions with LC-OCT showed no difference in performance in comparison to RCM, making LC-OCT a useful tool to discriminate between nevi and melanomas. There has been a tremendous development in the field of non-invasive in vivo imaging in Dermatology. From early detection of skin cancer to staging or diagnosing skin diseases, non-invasive imaging methods support clinicians in their daily practice and decision making. For the future an expansion of application to the inflammatory field of Dermatology is intended. In a prospective study we recently analyzed the applicability of non-invasive imaging tools in the diagnosis of onychomycosis. Further research in this field is necessary and potential new applications could entail inflammatory dermatoses like psoriasis and atopic dermatitis. Moreover, the influence of artificial intelligence in this fast-evolving research field could be further investigated. A first approach was made with artificial intelligence-based PRO score assessment in actinic keratosis. Whilst this was a first step towards a new chapter of non-invasive imaging, there will be numerous potential applications of artificial intelligence to be investigated in the future in this continuously advancing field of Dermatology.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften ; 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• Fakultäten: Medizinische Fakultät
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 19. September 2024
• 1. Bericht­erstatter:in: Sattler, Elke