Introductory Chapter: Dermatoscopy

1. Introduction

Although dermatoscopy was born as epiluminiscence microscopy many decades ago, it still develops, and hundreds of new papers are being published each year in scientific journals on new discoveries, significance of particular structures, and new applications. Dermatoscopy is no longer just a skin cancer screening technique, but can be employed to a wide variety of non-neoplastic conditions: trichoscopy for the diseases of hair and scalp, inflammoscopy for inflammatory skin diseases, mucoscopy for mucous membranes, onychoscopy for the diseases of nail apparatus, infectoscopy for identification of inflammatory diseases, endomodermatoscopy for skin parasitoses, and even dentoscopy for examining the teeth [1, 2, 3]. The systematization of the terminology in dermatoscopy and inflammoscopy terminology made the method more accessible for the beginners [4, 5].

2. The scope of dermatoscope

We are living in the era of Internet, smartphones, and artificial intelligence (AI)-driven networks that shape our practices and everyday environment to make it seemingly more convenient and remote, and COVID pandemic accelerated this process even more. In this chase, we are gradually losing the direct contact with our patients, which might lead to delayed or imprecise diagnosis of skin conditions. While taking advantage of what the modern technology provides us with, we should keep in mind that the simplest and direct examination, including taking medical history, visual inspection, and palpation, should still remain a gold standard. Dermatoscope is fast to apply and inexpensive auxiliary tool that complements physical examination and gives a better insight into the true nature of the inspected lesion. Nowadays, in many situations, dermatoscopists are able to diagnose certain diseases or predict a number of details commonly provided in pathology reports without actually taking a biopsy. Dermatoscopes proved to be useful in multispecialty settings. These can be used by dermatologists, oncologists, surgeons, general practitioners, radiotherapists, urologists, hematologists, pathologists, and many more. Being able to identify dermatoscopic structures can be the first step into pattern analysis and learning dermatoscopy-pathology correlations [6, 7, 8]. Currently, it is possible to assess tumor margins better than with a naked eye, which lowers the costs of treatment and lowers the risk of recurrence after radiotherapy and skin surgery, especially in Mohs micrographic surgery [9, 10, 11, 12, 13, 14]. Particular structures, such as pigmented clods, or vascular clues, can be predictors of more invasive basal and squamous cell carcinomas (BCC, SCC) [15, 16, 17, 18, 19, 20]. Consequently, it has an impact on planning the management (namely choosing between the surgery, topical treatment, radiotherapy, or photodynamic therapy) or monitoring its efficacy [21, 22, 23, 24]. Dermatoscopy always provides meaningful information. It may either confirm or rule out initial clinical diagnosis or point out to the other diagnosis that was not considered initially, especially inflammatory skin diseases. Even if the lesion turns out to be mysterious to the eye of dermatoscopist, dermatoscopy may exclude some of the diagnoses and lead to change in the diagnostic plan and management, influencing the decisive process (e.g., rapid biopsy)and saving the patient from the consequences of diagnostic pitfall, unnecessary expenses for non-optimal therapy and its side effects, lost time till the final diagnosis, unnecessary stress and suffering, and in some cases, also patient’s life/health from disease progression.

When combined with a device to capture images (smartphone, single-lens reflex camera, compact camera, or more convenient professional video dermatoscope) it proves to give additional info on already excised lesions. With a digitized image, physician is able to verify his initial diagnosis and reconsult the slides with the pathologist in order to avoid medical errors if the initial diagnosis does not match the report. It enables the identification of cases of mismatched specimens, misdiagnosis, or invalid tumor subtype. Also, based on the significance of the spectrum of colors seen in dermatoscopy, it is possible to detect underestimated Breslow thickness, as gray and blue colors mark the distribution of melanin in papillary and reticular dermis [25]. This process of confronting certain digitized features with the pathology can be called retroscopy, which is also a useful method to learn the morphology-histology correlations. Digital dermatoscopy or monitoroscopy can also be used for monitoring inflammatory skin diseases, predicting the therapeutic outcomes and resistance/susceptibility to certain therapies [26, 27]. AI is being increasingly implemented in all areas of healthcare. AI-assisted wide area digital dermatoscopy is a method enabling to combine multiple separate dermatoscopic images of the same large skin lesion into one map to enable precise assessment of structures and delineation [28, 29, 30]. Assessing the borders in melanoma is crucial for radical excision. In some lesions, this border is vague, but dermatoscopy with wavelengths close to ultraviolet light is able to enhance this process [31]. Another computer-assisted add-on to dermatoscopy and inflammoscopy is skin parameter map obtained with multispectral dermatoscopy [32, 33, 34]. Pattern recognition algorithms may have a particularly important role in the future development of digital dermatoscopy, supporting the diagnostic process and assisting the management, especially for non-experts [35]. This applies not only to AI-assisted assessment of dermatoscopic images but also photographs obtained with total body photography (TBP) [36, 37, 38, 39, 40]. Combining sequential TBP with the sequential digital dermatoscopy imaging increases the accuracy of detection of smaller, less invasive melanomas but also reduces the number of unnecessary surgical procedures [41]. As handheld dermatoscopy is cost-effective, easy to apply and learn, it is this diagnostic technique that should serve as a basic auxiliary device in skin cancer screening.