647 Clinical analysis of Hidroacanthoma simplex

Abstract

Objective: To investigate the clinical, histopathological findings, immunohistochemical features and therapeutic methods of hidroacanthoma simplex (HS). Methods: The clinical presentation, histological findings, immunohistochemical features and therapeutic methods of 5 patients with HS diagnosed between January 2015 and August 2020 in the Second Affiliated Hospital of Xi”an Jiaotong University and 17 patients with HS reported in the literature searched in CNKI were retrospectively analyzed. Results: Mean age at onset of the skin eruption was 62 years (range 36-86 years), 14 patients (63.6%) were female, and the skin lesion had been present for a mean of 7.84 years (range 5 months-50 years). Typical clinical findings were keratotic plaques mainly distributed the lower extremities and the trunk. Skin biopsy specimens from 22 patients showed the “Jadassohn phenomenon” and was composed of bland basaloid cells that were smaller than neighboring epidermal keratinocytes. Intracytoplasmic glycogen and occasional ductal structures within the nests of cells were also found. And one case (4.5%) was diagnosed as malignant HS. Immunohistochemically, the cytoplasm of some tumor cells showed a positive reaction to EMA and the normal ductal structure showed a positive reaction of CEA. Most patients (81.8%) chossed surgical resection and no recurrence and malignant transformation in follow-up. Conclusion: HS is a rare intraepidermal benign tumor, but it has risk of malignant transformation. And this disease mostly occurs in female patients, which is different from previous literature reports. For dermatologists, it is extremely important to correctly recognize and diagnose this disease.