A 52-year-old woman consulted for an asymptomatic erythematous-pink papule that had arisen 3 years earlier on the posterior aspect of her right lower limb. The lesion was round, with lobulated borders, and measured 1×1cm. (Fig. 1).

Figure 1.

Pink papule measuring 1cm in diameter on the posterior surface of the right lower limb.

(0.07MB).

Dermoscopy revealed a well-defined, erythematous-pink tumor (Fig. 2A) with prominent, more or less evenly distributed blood vessels, with characteristic cherry blossom images mostly at the periphery of the tumor (Fig. 2B), and pale pink structureless areas (Fig. 2A). With a suspected diagnosis of eccrine poroma, the lesion was excised and the histological findings confirmed the diagnosis. Eccrine poroma is an adnexal tumor derived from the intraepidermal eccrine duct or acrosyringium. It is typically located on the palms, soles, or fingers.1 Pigmented variants have been reported; clinically and dermoscopically these can mimic a pigmented basal cell carcinoma or malignant melanocytic lesion.2 The differential diagnosis of the nonpigmented variant includes basal cell carcinoma, squamous cell carcinoma, and hypo- or amelanocytic melanoma.

Figure 2.

A, Dermoscopic image showing structureless pale pink areas (asterisks) within the lesion and prominent peripheral vascularity. B, Detail of the blood vessels with the characteristic cherry blossom images.

(0.15MB).

A number of dermoscopic patterns and structures have been associated with this tumor, almost all of them referring to the vessels in the lesions: glomerular vessels, hairpin vessels, and linear irregular vessels. Some authors draw attention to the presence of a whitish halo around these vessels, as occurs in keratinizing lesions, but which, in this context, corresponds histopathologically to the presence of perivascular fibrinoid edema.1 Chalice-form vessels, frog egg-like round structures and cherry blossom vessels, sometimes difficult to differentiate from the chalice-form vessels have also been described.3,4 The presence of structureless whitish-pink areas is a common finding, corresponding histopathologically to areas of dermal lamellar fibroplasia. Although the vessels in eccrine poroma are similar to those in melanoma, the distribution tends to be more regular and symmetrical in eccrine poroma. Another finding that facilitates differentiation of these 2 tumors is that blood vessels are present in the milky-red areas of melanoma. In addition, structures exist in eccrine poroma that have not been described in melanoma (chalice-form vessels, and frog egg-like and cherry blossom structures). Other structures, such as chrysalids,5 are not present in eccrine poroma. In conclusion, we consider this case interesting as it demonstrates how the presence of 2 dermoscopic features (structureless pink areas and cherry blossom vessels) made a presumptive diagnosis of eccrine poroma possible. However, we believe that any nonpigmented lesion with prominent vascularity should undergo histopathological study due to the possibility of an amelanotic melanoma.6