High-resolution musculoskeletal ultrasonography and elastography for eosinophilic fasciitis diagnosis and follow-up: a case-based review.

Eosinophilic fasciitis (EF) remains a rare condition without precise diagnostic criteria due to common symptoms with other autoimmune diseases requiring broad differential diagnosis. This paper describes the use of high-resolution musculoskeletal ultrasonography and elastography in the diagnosis and follow-up of eosinophilic fasciitis through the case of a 56-year-old male patient. In addition to laboratory data, instrumental data, and biopsy, musculoskeletal ultrasonography (US) was used both in the diagnostic process and in the follow-up period for an objective assessment of the changes in the patient's condition and response to treatment. The US showed disorganization of the myofibrils adjacent to the superficial fascia, edema, and thickening of the fascia and subcutaneous edema. In addition, the use of shear-wave elastography (SWE) demonstrated significantly reduced skin elasticity. High-frequency musculoskeletal ultrasound in combination with SWE is an effective method both for the diagnosis of EF and for the follow-up of the changes occurring after therapy. Based on the fact that it can easily differentiate the substrate of involvement, such as skin, subcutaneous tissue, or muscle fascia, ultrasound can be used to distinguish EF from other skin and muscle diseases.