Value of High-Frequency Ultrasound in Accurate Staging of Mycosis Fungoides/Sézary Syndrome

Objectives: This study was aimed to assess the ultrasound (US) characteristics of mycosis fungoides (MF)/Sézary syndrome (SS) and explore the value of high-frequency US in accuracy staging for classic mycosis fungoides (cMF).

Methods: A prospective study was designed. Twenty-six patients with histopathologically confirmed MF or SS were enrolled to undergo HF-US examinations. Both 50- and 20-MHz US images of the most prominent lesion of each patient were collected by a cutaneous diagnostic US system, and the US characteristics in different stages were analyzed by 2 physicians independently. The Fisher exact test was used for the statistical analysis.

Results: A total of 26 patients underwent this study, including 23 with cMF, 2 with folliculotropic mycosis fungoides (FMF), and 1 with SS. Among cMF, 16 patients with patches or plaques (the early-stage group) showed a subepidermal low-echogenic band, and only 3 lesions in the plaque stage partially extended to the superficial dermis. Seven patients with tumors (the advanced-stage group) showed lesions that infiltrated to the deep dermis or subcutaneous tissue. The infiltration depth (P < .001), clarity of the boundary (P = .002), and homogeneity of internal echoes (P = .001) were significantly different between the early and advanced stages. Additionally, the 2 FMF lesions and 1 SS lesion had characteristic manifestations, showing a well-defined subepidermal low-echogenic band with patchy hypoechoic regions around the hair follicles in the dermis.

Conclusions: High-frequency US can be used to accurately detect the infiltration depth and morphologic features of MF/SS lesions and provide important information for tumor staging of cMF. Additionally, the characteristic US features in FMF and SS might be helpful for diagnosis.