Malignant form of hidroacanthoma simplex: A case report

BACKGROUND: This paper presents a case of malignant hidroacanthoma simplex (HAS) and review the literature of previous cases to summarize the histopathological and immunohistochemical features and display the dermoscopic features of malignant HAS. CASE SUMMARY: We present an 88-year-old Asian female with malignant HAS. The diagnosis was made according to the histopathological and immunohistochemical results after biopsy. Previous case reports of malignant HAS were retrieved from PubMed to characterize the histopathological and immunohistochemical features. We also display the dermoscopic features of malignant HAS that have not been reported. CONCLUSION: Our findings demonstrate that prompt surgical treatment is an effective strategy for malignant HAS. Histopathology and immunohistochemistry are valuable diagnostic tools. This is the first case report to display the dermoscopic features of malignant HAS, and we speculate that dermoscopy may contribute to the diagnosis of malignant HAS.