Background/Purpose:

Eosinophilic fasciitis (EF) presents with pain and induration of the skin. Currently the clinical diagnosis is based on typical physical findings along with MRI enhancement of the fascia, and the diagnosis is confirmed by documenting fascial thickening and inflammation on tissue histology, including eosinophilic infiltrates. A recent case report has suggested fascia thickness can be measured with use of MSK ultrasound. Changes in compressibility of subcutaneous tissue using a high-frequency probe have been shown to help distinguish it from scleroderma patients. Objective: To describe a cohort of 7 patients with MSK US finding supporting the diagnosis of eosinophilic fasciitis with corresponding MRIs findings compared with normal controls.

Methods: 7 patients with suspected EF seen in our rheumatology clinic underwent MSK US of upper or lower extremities that exhibited findings of induration suggestive of EF. An ultrasound was performed using a 12-18 MHZ linear array transducer to visualize muscle and fascia in the area of pain and induration. A measurement of fascial thickness was recorded in all patients. MSK US was also performed in 7 healthy controls. Patients subsequently underwent MRI of the same region. Full thickness skin to muscle biopsy to confirm the diagnosis was performed in 6 out of 7 cases (one patient refused biopsy). Initial labs with serum eosinophils were recorded. None of the patients had Raynaud’s or showed clinical or laboratory findings of scleroderma.

Results: 4 females and 3 males were included. Mean age: 43.5. Absolute eosinophil values ranged from 1051-4780/microL. The mean thickness of the fascia was 0.43 cm (ranges 0.21-0.7 cm) versus 0.14 cm in normal controls (ranges: 0.11-0. 19 cm). All patients had MRI with contrast with evidence of thickened and enhanced fascia of the same region. Diagnosis of EF was confirmed with tissue histology in all cases in which biopsy was performed.

Conclusion: MSK US may represent a quick, safe, inexpensive and reliable diagnostic method for patient with suspected EF. It can also help locate the best site for biopsy.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/musculoskeletal-ultrasound-as-a-diagnostic-tool-for-eosinophilic-fasciitis-and-correlation-with-mri-findings/