Dermoscopy in Practice
I carry the dermoscope in my shirt pocket and use it constantly. I do not use the dermoscope to identify seborrheic keratosis or basal cell carcinoma. These lesions are more easily diagnosed by examination of the surface with the 10x ocular. Seborrheic keratosis have horn pearls that are sometimes obscured and more difficult to see with the dermoscope. The pearly nature and telangiectasis of basal cell carcinoma are clearly identified with an ocular. Finding little flecks of pigment with the dermoscope adds little to the accuracy for the diagnosis of basal cell carcinoma. Most vascular tumors are easily diagnosed with simple observation and magnification. Dermatofibromas are recognized by inspection and palpation.
How is the dermoscope most useful on a daily basis. Small macular brown lesions with a somewhat irregular border and some variation in pigmentation are common. The irregular border and variation in pigmentation is worrisome. In many instances the dermoscope reveals a net like pattern with lines that are of uniform width and pigmentation. One can feel quite confident that this pattern is benign and an excision can be avoided. This alone justifies the use of a dermatoscope. Well-advanced melanomas are at the other end of the spectrum. A diagnosis of malignancy is often straight forward but looking into these tumors and seeing the classic dermoscopic findings of melanoma confirms the Providers initial impression. The dermoscopic findings makes the examiner so confident that he may refer the patient for definitive treatment.
Atypical nevi offer the greatest challenge. These lesions in many instances fulfill the long established ABCD criteria for melanoma and they require careful, detailed and repetitive examination. Dermatologic specialist providers best manage patients with large numbers of atypical nevi. The dermoscope is essential for sorting out the different patterns of these bizarre nevi. Review the section here on atypical nevi and review the paper Dermoscopic Classification of Atypical Melanocytic Nevi (Clark Nevi) in the December issue of the 2001 Archives of Dermatology. This paper makes sense out of chaos. Many excisions will be saved by dermoscopic examination and followup of patients with atypical nevi.
It is most important to understand the limitations of the technique. It is easy to start feeling overconfident. The paper entitled Limitations of Dermoscopy in the Recognition of Melanoma in the February 2005 issue of the Archives demonstrates how early melanomas can be missed with dermoscopic examination. These early lesions had not developed any of the classic dermoscopic features of melanoma.
Once facility with the dermoscope is acquired the provider will feel naked without it.