2021 Volume 38 Issue 4 Pages 618-623
Eruptive syringoma is a rare type of syringoma, a benign tumor of the eccrine ducts, and is characterized by the presence of widespread hyperpigmented papules on the trunk with onset around puberty. Here, we report two cases of eruptive syringoma presenting with characteristic dermoscopic findings. Case 1 involved a 21-year-old man who had developed a widespread skin rash on his trunk around the age of 19 years. Clinical examination showed small brown papules spreading on the trunk and both axillae. The differential diagnoses included verruca plana and Darier's disease. Case 2 involved a 67-year-old man who had been aware of itchy brown papules on the trunk since he was in his twenties. Dermoscopy in cases 1 and 2 showed homogeneous light brown pigmentation with multifocal whitish areas and a delicate pigment network at the periphery, which are typical characteristics of eruptive syringoma. Histopathological examination showed numerous small ducts and islands of epithelium embedded in a fibrous stroma in the upper dermis. These findings were compatible with the diagnosis of eruptive syringoma in cases 1 and 2. On comparing the dermoscopic and histopathological findings of syringoma, the whitish area with unclear borders corresponded to the fibrous stroma in the upper dermis, and the unclear borders corresponded to the dermal lesion. Therefore, dermoscopy may be helpful to differentiate eruptive syringoma from other skin diseases that involve the presence of widespread hyperpigmented papules with intraepidermal lesions, such as verruca plana or Darier's disease.