Dermoscopic features of eccrine porocarcinoma arising from hidroacanthoma simplex

Abstract

Eccrine porocarcinoma is a rare cutaneous neoplasm that mainly affects elderly people and grows slowly over a long period of time but often experiences an accelerated growth phase. Eccrine porocarcinoma may arise de novo or evolve from a pre-existing benign eccrine poroma. We reported a 86-year-old Japanese woman presenting with two reddish-colored pendulated lesions on a keratotic light brown plaque on the right thigh. Dermoscopic examination of the light-brown plaque demonstrated many whitish globular structures in a light-brown background. At the two reddish-colored pendulated lesions, polymorphous and prominent vessel proliferation was observed together with irregularly shaped whitish negative network. Immunohistochemical study demonstrated a positive CEA staining at ductal structures and atypical clear cells of reddish nodules. A diagnosis of eccrine porocarcinoma arising in a pigmented hidroacanthoma simplex was eventually established, and the dermoscopic features of eccrine porocarcinoma from hidroacanthoma simplex was described for the first time.

Figure 1

Two reddish-colored pendulated lesions at the peripheries of a keratotic light brown plaque.

Figure 2

(a) Dermoscopic examination of the light brown plaque demonstrated a lot of whitish globular structures on the light brown background. (b) In the left pendulated nodule, prominent polymorphous vessels were observed together with irregularly shaped whitish negative network. (c) Vessels were more conspicuous and irregular in the right nodule.

Figure 3

Histopathologic examination of the flat pigmented plaque disclosed many well-defined nests within the epidermis. (HE ×200).

Figure 4

(a) In the right red nodule, the epidermis was prominently acanthotic with intraepidermal proliferation of clear cells and squamoid cells. Dermal invasion of atypical squamoid cells was partially apparent (HE ×20). (b) In the right red nodule, the tumor cells were focally positive for carcinoembryonic antigen (CEA, ×20). (c) In the right red nodule, markedly atypical cells proliferated and extended throughout the entire thickness of the acanthotic epidermis (HE ×400). (d) The atypical clear cells expressed CEA (CEA ×400). (e) The ductal structures expressed CEA (CEA, ×400).

Figure 5

In the left red nodule, although the atypical basaloid cells proliferated in the epidermis, there were no visible invasions in the dermis (HE ×40).