We performed polarized light contact and noncontact dermoscopy. The first examination revealed an intense general erythematous-pink tone mainly at the periphery, with abundant vascularization comprising both homogeneous erythematous areas and irregular linear vessels. The central area had a notable erythematous pale gray tone with homogeneous yellowish-white areas and less visible vascularization. In the contact study, the lesion took on a duller, milky-red tone with almost no vascularization. In the interior of the lesion, we could see very clear opposing delimited yellowish-white areas.

The lesion was removed, and histopathology revealed pilomatricoma.1–3

Pilomatricoma is a benign adnexal neoplasm of the dermis or subcutaneous cellular tissue derived from immature cells in the hair matrix. While the tumor usually appears before age 20 years, a second peak in incidence is observed at around the sixth decade. Clinically, it presents as a solitary papule or nodule on the head, neck, or upper limbs and is commonly found in transition areas between hairy skin and hairless skin. It may present in a wide variety of colors, ranging from flesh, erythematous, and violaceous to highly pigmented lesions. However, the main characteristic of pilomatricoma is its hard consistency, the result of frequent secondary calcification (Figures 1-4).

Figure 1.

Tumor that first appeared 4 months previously on the hairline of an adult.

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Figure 2.

Firm, shiny, and well-delimited erythematous-pink nodule measuring 8mm in diameter.

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Figure 3.

Dermoscopy showing alternate intense erythematous tones at the periphery, with prominent vascularization and irregular whitish areas in the center.

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Figure 4.

Contact dermoscopy shows that the marked vascular component has almost disappeared and that the predominant finding is whitish-gray structures on a pale pink background.

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Given that pilomatricoma is a benign tumor that is also very frequent in children, it is interesting to make the diagnosis based on noninvasive tests. Recent data indicate that while not specific, dermoscopy findings can help us to establish a suspected diagnosis. The most frequent dermoscopy findings are vascular structures. Also very common are homogeneous red areas, irregular linear vessels, and hairpin vessels, which are indicative of major vascular proliferation in the dermis. However, the most relevant findings are undoubtedly irregular whitish structures (including white projections) that are usually noticeable because of their very clearly defined shape and intense color. In histological terms, these structures correspond to areas of calcification, which are so typical of this tumor. Ulceration or bluish-gray structures can also be observed in a lower percentage of cases. In conclusion, the combination of a prominent vascular pattern with homogeneous reddish areas and irregular linear vessels with intense whitish-gray structures should point us toward a diagnosis of pilomatricoma.

The authors declare that they have no conflicts of interest.