Dear Editor, Poroma is a benign neoplasm, in which tumor cells differentiate towards poroid and cuticular cells of acrosyringium.A 79-year-old woman (case 1) presented with an 18 mm 9 14 mm, bulb-shaped, light pink semipedunculated nodule with ring-like blackish macules on her left temporal region ( Fig. 1a). A 58-year-old man (case 2) exhibited a similar 12 mm 9 12 mm, semipedunculated nubby nodule on his right temporal region (Fig. 1a). Dermoscopic examination revealed thick vessels and large blue-gray ovoid nests in both cases (a) (b) (c) (d) (e) Figure 1. (a) Clinical images of cases 1 (left) and 2 (right). (b) Dermoscopic images of cases 1 (left) and 2 (right). Arrows indicate arborizing-like vessels; arrowheads, blue-gray ovoid nests. (c) Reflectance confocal microscopy of case 2 shows congested cells (white arrow) with small black holes (white arrowheads) without a palisading pattern at the periphery of the tumor nests. (d)Histopathological images of cases 1 (left) and 2 (right) (hematoxylin-eosin). In more detail, the features of two subtypes of the tumor, poroma and dermal duct tumor, are observed in case 2. Melanin granules are found mainly in the upper to middle dermis forming clusters, probably reflected in the dermoscopic structures of relatively smooth and homogeneous blue-gray ovoid nests shown in (b). Arrows, poroid cells; arrowheads, cuticular cells (bars, 100 lm). (e) Dermoscopic images of the nodules alongside the noses of the other two patients, cases 3 (left) and 4 (right). Both of these nodules were histopathologically demonstrated to be typical nodular basal cell carcinoma (data not shown). Arrows, arborizing vessels; arrowheads, blue-gray ovoid nests.

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Interestingly, a similar phenomenon was observed in this case. Regular hairpin vessels are seen in seborrheic keratosis. 1,5 This melanoma was accompanied by senile lentigo, which can be the precursor of seborrheic keratosis. It may be one of the possible mechanisms by which regular hairpin vessels become conspicuous by melanoma. Recently, black-blue color has been reported to be an important dermoscopic clue to recognize nodular melanoma. 2 However, black-blue color was uncertain probably because this case was hypomelanotic melanoma and such a confusing case still may exist. We should keep in mind that typical dermoscopic features of pigmented basal cell carcinomas can be found in melanomas.