Table 1.

Dermoscopic Clues That Differentiate Trichilemmal Cyst from its Main Differential Diagnoses

Lesion	Classic Dermoscopic Criteria
Trichilemmal cyst	Pinkish-yellow or homogeneous yellowish-white background Peripheral erythematous halo Absence of pore sign Blue pigmentation (Tyndall effect of keratin)
Epidermal cyst	Yellowish-white papule Pore sign: keratin-filled, circular orifice, whitish, yellow, brown or black in color Wobble sign (movement of the lesion with respect to the surrounding tissues, except for the pore, which represents the site of anchorage of the cyst)
Basal cell carcinoma	Arborizing vessels, sort fine telangiectasias Ulceration, erosions Maple-leaf like, spoke-wheel and concentric structures Blue-gray globules, blue-ovoid nests
Squamous cell carcinoma	Presence of keratin, especially in conjunction with blood spots Coiled vessels White structureless zones, white circles (highly differentiated SCCs) Predominantly red color, bleeding and ulcerations (poorly differentiated SCCs)
Syringoma	Yellowish-brownish structures Structureless background Reticular vessels
Sebaceous hyperplasia	Central umbilication surrounded by aggregated polylobular white-yellowish structures (cumulus sign); this global appearance is known as bonbon toffee sign Surrounding crown of vessels at the periphery

SCC = squamous cell carcinoma.