Keratoacanthoma

Excerpt

Keratoacanthoma (KA) is a low-grade, rapidly growing, 1 to 2 cm dome-shaped skin tumor with a centralized keratinous plug. Over the past hundred years, this tumor has been reclassified and reported differently throughout literature. Before 1917, keratoacanthoma were regarded as skin cancer. In the 1920s, reports labeled the tumor as verrucae or vegetating sebaceous cyst. Between 1936 and the 1950s the lesion was labeled and reported in the literature as molluscum sebaceum.

Keratoacanthoma is characterized by initial rapid growth followed by a period of variable tumor stability and spontaneous regression. Keratoacanthoma is further divided into different subtypes with different presentations. Subtypes include solitary keratoacanthoma, subungual keratoacanthoma, mucosal keratoacanthoma, giant keratoacanthoma, keratoacanthoma centrifugum marginatum, generalized eruptive keratoacanthoma of Grzybowski, and multiple keratoacanthomas Ferguson-Smith syndrome. Although recognized as benign, KA shares histopathological features with squamous cell carcinoma (SCC) requiring treatment.