Dermoscopy and its role in diagnosing melanocytic lesions: a guide for pathologists

Cutaneous Imaging Techniques

Cutaneous imaging is a central tenant to the practice of dermatology. In this article, the authors explore various noninvasive and invasive skin imaging techniques, as well as the latest deployment of these technologies in conjunction with the use artificial intelligence and machine learning. The authors also provide insight into the benefits, limitations, and challenges around integrating these technologies into dermatologic practice.

Slit lamp polarized dermoscopy: a cost-effective tool to assess eyelid lesions

PURPOSE

Dermoscopy is a complementary examination of skin lesions, which allows the observation of anatomical features invisible to the naked eye. Its use increases the diagnostic accuracy of skin tumors. The development of polarized dermoscopy allowed the observation of deeper skin structures, without the need of skin contact. The purpose of this study was to present a low-cost prototype through the adaptation of polarized lenses on a slit lamp in order to assess anatomical aspects invisible to conventional biomicroscopy in eyelid lesions.

METHODS

Twenty two eyelid lesions were documented using a prototype, compound of two polarizing filters, orthogonal to each other, adapted to a slit lamp with an integrated digital camera. Images of the eyelid lesions were also obtained with non-polarized biomicroscopy and with a portable dermatoscope, and were compared regarding anatomical aspects.

RESULTS

Anatomical structures imperceptible to conventional ophthalmic examination were evidenced using the polarized lenses, demonstrating that this tool can be useful to the ophthalmologist when assessing eyelid lesions. We have obtained high-quality images of the lesions. The slit lamp provided higher magnification, better focus control and easier assessment of eyelid lesions than the portable dermatoscope.

CONCLUSION

Ophthalmologists already use the slit lamp in their practice. The adaptation of polarized lenses to this device is a cost-effective, fast and non-invasive method that permits to improve the diagnostic accuracy of eyelid lesions, evidencing anatomical structures imperceptible to conventional ophthalmic examination.

Basal cell carcinoma and dermal nevi of the face: comparison of localization and dermatoscopic features

BACKGROUND

Basal cell carcinoma (BCC) and dermal nevi located on the face can easily be confused on clinical examination. Little is known about the different preferential localizations of these entities, and a systematic analysis of dermatoscopic features for differential diagnosis is lacking.

METHODS

Clinical and dermatoscopic images of BCCs and dermal nevi were retrospectively evaluated to study their relation to various face anatomical areas, BCC histotype, classic and nonclassic dermatoscopic BCC criteria, as well as typical dermatoscopic criteria for dermal nevi.

RESULTS

We examined 118 BCCs and 77 dermal nevi, all having histopathological confirmation. BCCs were most frequently located on the lateral side of the forehead (12.7%), nasal dorsum (10.2%) and nasal ala (9.3%), while dermal nevi were found predominantly on the buccal area (11.8%), scalp (11.8%), and perioral region (10.8%). The prevalent dermatoscopic criteria for BCC were the classic arborizing vessels (94.1%) and arborizing microvessels (89%). The most common BCC histotype on the face was sclerodermiform (47.5%), followed by nodular (28%) and superficial (24.6%).

CONCLUSIONS

This study shows that BCCs are preferentially located on the lateral side of the forehead, nasal dorsum and nasal ala, while dermal nevi of the face are preponderantly located on the buccal area, scalp, and perioral region. The dermatoscopic features confirmed the frequency of classic and nonclassic criteria for BCCs already demonstrated in other studies. No significant site-specific features were observed for either BCCs or dermal nevi.

Lichen planus-like keratosis: clinical applicability of in vivo reflectance confocal microscopy for an indeterminate cutaneous lesion

Lichen planus-like keratosis (LPLK) is an involuting cutaneous lesion often presenting between the fifth and seventh decades of life. These lesions typically appear abruptly as a solitary macule, papule, or plaque that continuously evolves as it undergoes regression. Clinical and dermoscopic features of LPLK can mimic both benign and malignant lesions, often prompting biopsy for accurate diagnosis. We describe a case of LPLK developing in a patient with a history of multiple skin cancers, including melanoma. Dermoscopy revealed peripheral granules and a central area with pinkish-brown pigmentation and a disorganized pattern with shiny white structures and rosettes. Handheld reflectance confocal microscopy (RCM) showed a typical honeycomb pattern with millia-like cysts and comedo-like openings, and lacked pagetoid and dendritic cells. Based on the benign features seen with RCM, the lesion was followed until complete regression was observed. In conclusion, we describe a case of LPLK with clinically and dermoscopically indeterminate features that was successfully monitored with RCM. We intend to highlight the utility of RCM as a diagnostic aid in equivocal lesions in order to prevent unnecessary excisional procedures.

Up-to-date non-invasive visualization technologies in dermatology

The authors present a review of up-to-date non-invasive visualization methods used in diagnostics of diseases of skin and its appendages. They describe physical principles forming the basis for non-invasive visualization methods such as dermatoscopy, confocal laser scanning microscopy, optical video monitoring, optical topometry, optical coherent tomography, ultrasound scanning, 3D-modeling. They also describe the potential of practical application of these diagnostics methods at the current stage of their development. The authors have demonstrated that it is possible to reduce the clinicians need in biopsy diagnostics due to the high information value of non-invasive visual diagnostics methods.

The real-time, three-dimensional analyses of benign and malignant skin tumors by confocal laser scanning microscopy

BACKGROUND

In obtain images of skin tumors non-invasively with real-time, confocal laser scanning microscope (CLSM) is introduced.

OBJECTIVE

Reconstructed images of given horizontal sections were converted into three-dimensions using the data set of a large number of tomograms in the horizontal directions.

METHODS

To develop the multiplaner reconstruction images of skin tumors in vertical directions and three-dimensionally reconstructed images of tumors will be obtained from the continuously collected horizontal image data sets.

RESULTS

Three-dimensional analyses of the skin tumors from reconstructed images of the CLSM scanning have provided the information as to their physiological characteristics as well as the extent of deep invasion in real-time with non-invasive manner. High performance three-dimensional conversion software was effective in displaying three-dimensional construction of skin tumors.

CONCLUSION

The CLSM scanning images followed by three-dimensional reconstruction using them can provide the real-time and non-invasive diagnoses of skin tumors and analyze the radial growth phase of tumors and the three-dimensional growth characteristics.

Correlation with digital dermoscopic images can help dermatopathologists to diagnose equivocal skin tumours

BACKGROUND

A variety of pigmented skin tumours can lead to diagnostic difficulties in dermatopathology.

OBJECTIVES

To investigate whether the interobserver agreement between histopathological diagnoses of equivocal pigmented tumours made by two referral centres can be improved by additional use of dermoscopic images.

MATERIAL AND METHODS

Retrospective study using 160 tumours excised in the pigmented skin lesions clinic in Graz and 141 from Tübingen. Tumours were diagnosed in the referring centres using clinical data, histopathology and, if required, immunohistochemistry. The tumours were initially diagnosed as 74 melanomas, 218 melanocytic naevi and nine nonmelanocytic tumours. Haematoxylin and eosin sections, patients' age and sex, tumour localization and digital dermoscopic images were then exchanged between the participating centres. Then, diagnoses were made initially based solely on dermatopathology and clinical information. After a washout phase, the same sections were reevaluated with the additional use of dermoscopic images. The main outcome measures were the Cohen's kappa-coefficients of the initial diagnoses of the centre submitting the cases and the diagnoses of the other centre without and with dermoscopy.

RESULTS

The kappa-coefficient between the initial diagnoses with those made by the second centre without dermoscopy was 0.90 in Graz, 0.73 in Tübingen, and 0.81 overall. With the additional use of dermoscopy the kappa-value was invariably high with 0.89 in Graz, and improved to 0.87 in Tübingen, and to 0.88 overall.

CONCLUSIONS

The additional use of digital dermoscopic images further improved the overall very good agreement of histopathological diagnoses between two referral centres.

Cutaneous melanoma

Episodic exposure of fair-skinned individuals to intense sunlight is thought to be responsible for the steadily increasing melanoma incidence worldwide over recent decades. Rarely, melanoma susceptibility is increased more than tenfold by heritable mutations in the cell cycle regulatory genes CDKN2A and CDK4. Effective treatment requires early diagnosis followed by surgical excision with adequately wide margins. Sentinel lymph node biopsy provides accurate staging, but no published results are yet available from clinical trials designed to assess the therapeutic efficacy of early complete regional node dissection in those with metastatic disease in a sentinel node. Magnetic resonance spectroscopy is one technique under investigation for non-invasive, in-situ assessment of sentinel nodes. Localised metastatic disease is best treated surgically. No postoperative adjuvant therapy is of proven value for improving overall survival, although numerous clinical trials of vaccines and cytokines are in progress. Medical therapies have contributed little to the control of established metastatic disease, but molecular pathways recently identified as being central to melanoma growth and apoptosis are under intense investigation for their potential as therapeutic targets.