What is a Dermatoscope?

A dermatoscope or a skin surface microscope is a non invasive handheld magnification tool. It is directly placed on the surface of the skin of the patient to examine the key morphological structures of skin lesions that are on and below the skin surface that are not easily visible to the naked eye. It allows direct viewing and analysis of the epidermis and papillary dermis.

The dermatoscope magnifies the sub surface structures with the use of oil and illumination, also known as epiluminescence, on the skin interface. The dermatoscope facilitates the clinical diagnosis of all pigmented and non-pigmented lesions from melanoma cancer, to acral skin and even the nail apparatus. Dermatoscopy is a particularly helpful standard method of diagnosing the malignancy of skin lesions.

Non-invasive skin imaging mechanisms have been in relatively widespread use for the last 10 years. The dermatoscope as a diagnostic aid for pigmented lesions has the most clinical efficacy. A dermatoscopic examination can also be conducted using polarized light without the requirement of any liquid interface. A dermatoscope when used with a videomicroscope for computer evaluation of melanomas may also be known as a “mole scanner”.

Advantages of Dermatoscopy

With doctors who are experts in the specific field of dermoscopy, the diagnostic accuracy for melanoma is significantly better than for those dermatologists who do not have any specialized training in dermatoscopy. Thus, with specialists trained in dermoscopy, there is indeed a considerable improvement in the sensitivity or detection of malignant melanomas as well as specificity or percentages of non-melanomas correctly diagnosed as compared with the traditional clinical naked eye examination.

Studies conducted have revealed that the accuracy by dermatoscopy was increased by 19% in the case of sensitivity and by 6.2% in the case of specificity. It also goes to show that detection of undiagnosed melanomas by the naked eye method is greater compared to the detection of benign lesions. By using dermatoscopy the specificity is thereby increased reducing the frequency of unnecessary surgical excisions of benign lesions.

Dermatoscopy Reduces the Need for a Biopsy

Compared to only naked eye examination in detection of melanoma conducted by dermatologists, naked eye examination coupled with dermatoscopy reduces the number of patients referred to for biopsy or excision by a significant 42%. There is a sizeable decrease in the benign-malignancy ratio of excised lesions from 18:1 where dermatoscopy is not used to 4:1 where it is used. This proves that, compared with the naked eye examination, dematoscopy not only detects melanomas more effectively but the need for unnecessary biopsy on benign lesions is considerably reduced as well.

Dermatoscopy as an aid to Histopathology

Dermatoscopy acts as a link between clinical examination and histopathological examination. Analysis of skin lesions using histopathological examination is considered as a gold standard. However, in cases where histopathological examination was inefficient in regard to analysis of certain sections, dermatoscopy correctly diagnosed the problems. So areas, which are suspected to be problematic, are detected dermatoscopically and thus aids the pathologists in helping them decide whether or not to perform sections in those particular areas.

Sequential Digital Dematoscopy

This is a more recent and advanced technique whereby early incipient melanoma can be detected thereby allowing faster initiation of therapy. Digital dermatoscopes are instruments with which sub surface skin images can be taken digitally. These images are shown in a sequential pattern on the screen of the computer. The melanocytic lesions, which are visible on screen can be analysed over time to see if they develop any malignancy. Both short and long term digital dermatoscopy methods are in use. These are extremely helpful in the sense that they permit detection of melanomas that do not seemingly have clinical features of malignant melanomas in the early stages and thus can not be detected with only a naked eye examination.

Thus, the advantages of dermatoscopy compared to the naked eye examination method are fourfold. The normal skin can be examined as it really is. Also, pathological conditions like inflammation and any alterations in size of lesions can be analyzed and calculated accurately. Moreover, these can be monitored in a non-invasive manner alongside the ongoing treatment. Most importantly, dermatoscopes act as accurate devices for diagnosis of pigmented lesions and enables determination of the need for biopsies and aid decisions on effective treatment approaches.