Dermoscopy of eccrine poroma with calcification

Background: Eccrine poromas are relatively common slow-growing benign solitary adnexal tumors originating from the intraepidermal portion of the eccrine sweat duct (acrosyringium). Dystrophic calcification is rarely found in lesions of eccrine poroma, and only 2 cases of eccrine poroma with calcification have been reported thus far. In the present report, we describe another case of eccrine poroma with calcification occurring in the palm of the hand. Also, we show dermoscopic features of this case. Main Observations: A 73-year-old man with hemiparesis, who had a 10-year history of tumor on his right palm, which was occasionally injured by a walking crutch, causing bleeding and ulceration. Physical examination revealed a pigmented dome-shaped tumor. Dermoscopic analysis revealed glomerular vessels, multiple pink-white structureless areas, and lacunae. Histological examination revealed that the tumor was composed of cords of tumor cells extending from the epidermis into the dermis. These were uniformly cuboidal cells with round, basophilic nuclei and dense vascular stromas with telangiectasia. The tumor showed cystic structures and calcification. The patient was diagnosed with Pinkus-type eccrine poroma on the basis of histological findings. Conclusion: Although cutaneous neoplasms commonly associated with calcification are of follicular origin, it is known that dystrophic calcification may be triggered also in tumors of eccrine origin by multiple factors, including mechanical injury. Dermoscopy may be helpful in establishing clinical diagnosis of calcified eccrine poromas.