Keratoacanthoma: A review of the literature

Keratoacanthoma (KA) is a common, rapidly growing cutaneous neoplasm which most likely develops by abnormal proliferation of the follicular epithelium or the epidermis. Although most of the KA's involute over a period of 2 to 6 months, locally aggressive lesions or recurrences and even metastases have been reported. The role of human papilloma virus in the genesis of this tumor appears uncertain, but immunosuppression appears to play a role in the development. The clinical and histological features of KA may closely mimic well-differentiated squamous cell carcinoma, particularly during the early active growth phase. Various immunologic markers such as blood group antigen H, histocompatibility complex antigens, CEA, peanut lectin receptor, involucrin and filaggrin are used to distinguish these tumors. Treatment modalities are numerous.