Ultrasound Characteristics of Keratoacanthoma: Differentiation From Well-Differentiated Cutaneous Squamous Cell Carcinoma.

Abstract

This study aims to describe the ultrasound characteristics of keratoacanthoma (KA), providing valuable insights for non-invasive diagnosis and differentiation from well-differentiated cutaneous squamous cell carcinoma (wcSCC). Ultrasound characteristics of 16 KA and 13 wcSCC conformed by surgical pathology were retrospective analyzed. KA patients were younger (mean age 63.13 years) compared with wcSCC patients (mean age 76.23 years). Ultrasound characteristics revealed that KA lesions were generally smaller, more frequently domed-shaped (87.50 vs 38.46%), exophytic (93.75 vs 30.77%), and well-defined (93.75 vs 53.85%) compared with wcSCC. Both lesion types predominantly showed hypoechoic internal echoes and inhomogeneous echotexture. The prevalence of hyperechoic superficial area was notably high in both groups (93.75 vs 84.62%), precluding the reliable use of this feature as a discriminatory marker between these two distinct neoplastic entities. KA lesions were mostly confined to the epidermis and superficial dermis (87.50%), while wcSCC cases frequently infiltrated into the subcutaneous fat layer (84.62%). Color Doppler imaging demonstrated higher vascularity in wcSCC lesions, with 61.5% showing Grade 3 flow, compared with KA lesions, where 62.5% exhibited Grade 2 flow. High-frequency ultrasound reveals distinct ultrasound characteristics differentiating KA from wcSCC, offering a promising non-invasive tool for preliminary diagnosis and treatment planning.