Ancillary techniques to improve dermoscopy specificity for skin cancer detection

Abstract

Although the use of dermoscopy has markedly improved both the sensitivity and specificity for skin cancer detection, there is still opportunity for improvement. Ancillary techniques provide additional ways to assess a lesion with the aim of improving our diagnostic ability with little extra cost. Usage of these techniques can strengthen diagnosis and help reduce unnecessary biopsies of benign lesions.

Figure 1

(a) Lesion suspected to be a dermatofibroma (DF); (b) the pinch test illustrates a positive dimple sign, supporting a diagnosis of DF.

Figure 2

(a) Dermoscopic view of a lesion suspected to be an intradermal naevus (IDN); (b) application of horizontal pressure causes the lesion to wobble, supporting the diagnosis of IDN.

Figure 3

(a) Dermoscopic image of a red/black lesion on the sole with a parallel ridge pattern; (b) scrape test performed using a blade to remove the stratum corneum from part of the lesion; (c) part of the lesion has been removed, confirming a diagnosis of subcorneal haematoma.

Figure 4

(a) Dermoscopic view of a darkly pigmented lesion with a central blotch; (b) appearance of the lesion following the adhesive tape test, revealing the reticular network of a benign naevus; (c) the pigmented stratum corneum has been removed and is visible on the tape.

Figure 5

(a) Dermoscopic image of a lesion composed of nonspecific brown clods; (b) following the ink test, the comedo-like openings become easily apparent, aiding diagnosis of a seborrhoeic keratosis.

Figure 6

(a) An annular skin lesion with unclear diagnosis; (b) following the ink test, deposition of ink within the furrow of the cornoid lamella confirms the diagnosis of porokeratosis.

Figure 7

(a) Dermoscopic view of a pigmented acral lesion; it is unclear whether the pigment predominates in the furrows or the ridges. (b) Ink is applied to the lesion as part of the furrow ink test; (c) when the ink is wiped away a parallel furrow pattern becomes evident, indicating a benign naevus.

Figure 8

(a) Dermoscopic image of a fibrillar-patterned pigmented lesion on the sole; (b) lateral pressure with the dermatoscope aligns the pigment back to a parallel furrow pattern, indicating a benign naevus.

Figure 9

(a) Nonpolarized dermoscopy revealed a largely featureless skin lesion; (b) toggling to polarized dermoscopy allowed identification of shiny white structures, aiding with the diagnosis of skin cancer, in this case a basal cell carcinoma.

Figure 10

(a) Shiny white structures (SWS) are visible with polarized dermoscopy (PD) but less prominent due to the orientation of the dermatoscope; (b) slow rotation of the dermatoscope up to 180 degrees while using PD can enhance identification of the SWS, in this case supporting a diagnosis of melanoma. This phenomenon is due to the angular dependence of polarized light.