“Stretching Dermoscopy” to Delineate the Margins of Basal Cell Carcinoma on Photodamaged Telangiectatic Skin

Introduction

Dermoscopy is widely used in clinical practice for basal cell carcinoma (BCC) diagnosis and has been shown to accurately predict the tumor subtype [1]. Furthermore, dermoscopy was shown to enhance the clinical preoperative assessment of peripheral margins, especially for pigmented BCCs [2]. In non-pigmented, the topographic evaluation of the vessels may be an important way to assess the tumor margins. Commonly, dermoscopy of non-superficial BCC reveals large linear ramified (arborizing) vessels that are usually well-focused and bright red, and superficial BCC displays thinner and shorter vessels, the so-called superficial fine telangiectasias [1]. In contrast, telangiectatic vessels from chronic sun damage are smaller, less focused and dull-red. However, when BCC develops on severely sun-damaged skin with numerous telangiectasias, it might be challenging to discriminate them from tumoral vessels and delineate the tumor [3].

Stretching the skin around the tumor has been proposed to improve the assessment of its margins by enhancing the macroscopic visualization of the opalescent color that corresponds to the stromal alterations of BCC (Figure 1) [4].

Figure 1.

Clinical presentation. (A) 63-year-old female patient, presenting with an ill-defined plaque on the upper cutaneous lip and signs of photodamaged skin as lentigines and telangiectasias in all sun-exposed areas of the face. (B) View when stretching the surrounding skin.

Although it can be reasonably hypothesized that combining skin stretching with dermoscopy might offer additional information and further improve the assessment of BCC margins, this is not supported by evidence up to date.

Case Presentation

We present a case that aims to suggest that combining both techniques might be superior to using each technique alone to delineate BCC margins prior to surgical removal in areas with a telangiectatic background. Figure 1A shows an ill-defined infiltrative BCC on the upper cutaneous lip of a 63-year-old female patient and Figure 1B depicts the same lesion after skin stretching.

In the standard non-contact polarized dermoscopic evaluation, tumor is evaluated without stretching the surrounding skin (Figure 2A). In “stretching dermoscopy,” the skin adjacent to the tumor is stretched during dermoscopic examination (Figure 2B). With this maneuver, the opalescent white structureless area of the BCC becomes more evident. In addition, the blood flow of the smaller vessels surrounding the tumor is reduced without compromising the larger arborizing vessels of the tumor, enhancing, thus, the discrimination between them (Figure 2). The pressure applied with contact dermoscopy can also achieve compression of UV-induced telangiectasias, but it may also compress the tumoral vessels, which are important for the diagnosis.

Figure 2.

Stretching Dermoscopy. (A) Non-contact polarized dermoscopy of a basal cell carcinoma on the upper cutaneous lip, with a telangiectatic background. (B) Dermoscopy after stretching the surrounding tissue. Note how the basal cell carcinoma is better visualized contrasting with the surrounding telangiectatic background. (C) The tumor margins as assessed after stretching dermoscopy. (D) Demarcation of the tumor boundary before excision. The excision was performed at the outer margin of the black ink.

Dermoscopy alone has been used for preoperative margin delineation of BCC during classic surgery and also to reduce the number of stages in Mohs micrographic surgery (MMS), but data on the latter are controversial {5,6]. Similarly, skin traction by itself has been described as an important preoperative step to maximize the contrast between BCC and surrounding normal skin during naked eye examination [4]. In the present case, the tumor was cleared after one stage of MMS.

Conclusions

We suggest that combining both techniques might be a simple and inexpensive way to enhance the preoperative examination in classic surgery or the first stage of MMS. However, our hypothesis needs to be evaluated by further studies assessing whether stretching dermoscopy allows for less incomplete excisions during classic surgery or reduced number of stages in MMS.