Ultrasound Features and Clinical Pathological Characteristics of Acquired Periungual Fibrokeratoma: Two Case Reports

Background: Acquired periungual fibrokeratoma (APF) is a rare benign neoplasm that can cause longitudinal nail plate malformation. Although the significance of high-frequency ultrasound (HFUS) in the assessment of nail unit lesions has been well - established, its sonographic characteristics remain insufficiently documented. To describe the sonographic characteristics of acquired periungual fibrokeratoma in two cases, offering early observations to inform future studies. Methods: Two patients with histopathologically confirmed acquired periungual fibrokeratoma were examined using high-frequency ultrasound (HFUS), and the sonographic features were correlated with clinical and histopathological findings. Results: High-frequency ultrasound (HFUS) accurately delineated the size, location, and morphology of acquired periungual fibrokeratoma as well-defined, hypoechoic, nail matrix-based nodules with minimal internal vascularity. Sonographic measurements closely matched gross specimens, demonstrating strong imaging–surgical correlation and supporting the utility of ultrasound in preoperative evaluation. Conclusion: High-frequency ultrasound (HFUS) revealed that the acquired periungual fibrokeratoma presented as a well-demarcated, hypoechoic nodule originating from the nail matrix, with minimal internal vascularity,correlating closely with histopathology. These findings add to the limited imaging literature, aid differentiation from other periungual tumors, and support preoperative mapping to protect the nail matrix. Routine use of HFUS is advocated to improve surgical outcomes and preserve nail apparatus function.