Advanced Dermoscopic Insights into Squamous Cell Carcinoma

Dermoscopy, a valuable diagnostic tool in dermatology, offers a more in-depth examination of the skin's surface, facilitating the identification of specific characteristics of both pigmented and non-pigmented squamous cell carcinomas (SCC). While the diagnosis of invasive SCC may not be solely reliant on dermoscopy, it plays a crucial role in distinguishing these malignancies from other skin conditions.

Dermoscopy in Actinic Keratosis Assessment

Actinic keratosis, often a precursor to SCC, can be identified through dermoscopy by the presence of a 'strawberry pattern,'dermoscopy of actinic keratosis which is characterized by a network of red lines surrounding yellowish hair follicles, each encircled by a bright white halo. This pattern is particularly evident on facial skin. Other indicators include a target-like appearance, pigmentation from grey or brown dots, and broken pseudonetworks that may resemble atypical lentigo. Additionally, short, curved red blood vessels and rosettes—clusters of four white, shiny spots around hair follicles—are indicative of sun-damaged skin.

On non-facial regions, these keratoses exhibit a consistent pink or tan backdrop with pronounced keratinization, appearing as white or yellow scales. The key dermoscopic features of actinic keratosis include:

Erythematosus pseudonetwork

Surface scale

Linear and wavy vessels

Yellowish ovoid follicular openings

Globular structures encircled by a white halo

Dermoscopy for Intraepidermal Carcinoma

Dermoscopy aids in identifying pigmented intraepidermal carcinoma, presenting as an irregular, scaly plaque with colors ranging from skin-toned to pink or brown. The presence of irregular clusters of 'glomerular vessels' or small red globular vessels is a distinctive sign. These may coexist with a scaly surface, small brown globules, linear grey dots, or homogeneous pigmentation, with pigmented structures often aligned in lines. Irregular clusters of white circles may also be observed, indicative of superficial erosion and crusting.

In the case of non-pigmented intraepidermal carcinoma, the diagnosis through dermoscopy is more challenging. Compared to basal cell carcinoma, there is increased scaling, and the vascular pattern is more glomerular/globular rather than the branching pattern seen in basal cell carcinoma. The background coloration tends to have an orange-pink hue, contrasting with the blue tones often associated with basal cell carcinoma. Polarized dermoscopy may reveal the absence of white 'crystalline' structures but can show rosettes on facial skin, indicative of keratin around follicles.

Dermoscopy in Invasive Squamous Cell Carcinoma

Invasive SCC presents a wide range of clinical appearances, influenced by the degree of differentiation and the location on the body. It often manifests as a thickened plaque or nodule. The ulceration may or may not be pronounced, with severely ulcerated tumors lacking discernible dermoscopic structures.

Poorly differentiated tumors tend to exhibit a pinker hue, while well-differentiated lesions appear whitish. Malignant tumors are characterized by their destructive nature, leading to a loss of normal tissue structure. The hallmark of SCC is keratinization, resulting in prevalent white, structureless areas. In well-differentiated tumors, including keratoacanthoma, there may be a central area of superficial scale or crust, surrounded by a paler, dull-white zone.

Irregular groups of white perifollicular circles are a typical feature of SCC.

Blood spots are commonly observed.

Blood vessels display a variety of irregular morphologies, including round, coiled, looped, serpentine, branched, or polymorphic patterns. A greater variation in vasculature is associated with a lower degree of histopathological differentiation.

The use of dermoscopy in the assessment of SCC enhances the diagnostic process, providing a clearer understanding of the lesion's characteristics and guiding appropriate treatment strategies.