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Scientific Session 13 — SS13: Musculoskeletal Imaging - Tumors

Wednesday, May 8, 2019

Abstracts 1216-2911

2721. Fibro-Adipose Vascular Anomaly: Old Wine or New Cocktail

GOYAL A*,  SANGWAN A,  KUMAR A,  SINGHAL M,  ARAVA S. All India Instititute of Medical Sciences, New Delhi, India

Address correspondence to A. GOYAL (ANKURGOYALAIIMS@GMAIL.COM)

Objective: Fibro-adipose vascular anomaly (FAVA) is a provisionally unclassified vascular anomaly (under International Society for the Study of Vascular Anomalies ISSVA Classification 2018) which is refractory to conventional treatments. The purpose of the study is to describe the clinical and radiological features of FAVA including the use of advanced imaging techniques.

Materials and Methods: In this ethically approved study, a retrospective review of the hospital records was done and yielded 20 patients with FAVA from January 2016 to March 2018. The diagnosis was based on multidisciplinary gold standard including presentation, imaging, and pathology in all cases. The clinical and imaging findings were reviewed.

Results: There were 7 male and 13 female patients (mean age, 20.2 years; range, 5-46 years). The lesion was located in the calf in 6 patients, thigh in 5, forearm in another five, torso in 3 and 1 patient had involvement of anterior knee. All patients presented with severe pain (mean VAS score, 7.2/10). Five patients had restriction of motion, and 4 of these also had limb contractures. The involvement was ill-defined in 11 patients, predominantly intramuscular in 18, and subcutaneous in 2 patients. All lesions were solid-appearing heterogeneous echotexture on ultrasound, and internal vascularity was seen in 12 patients on color Doppler. Contrast-enhanced US (CEUS) was done in 9 patients and showed heterogeneous enhancement in 8 of 9 patients and progressive enhancement in 6. Shear-wave elastography was done in 8 patients and showed the lesion was soft (mean elasticity, 18.4kPa). MRI showed areas of T1 hyperintensity mixed with T2 hyperintense regions in 13 of 14 patients. Dynamic CE-MR angiography revealed progressive heterogeneous enhancement in 7 of 9 patients, and delayed enhancement was seen in all. Phlebectasia was seen in 14 of 20 patients, and phlebograms done in 4 patients revealed dysplastic veins.

Conclusion: FAVA presents with unique clinico-radiological features, and tissue sampling serves to rule-out mesenchymal neoplasms. The typical clinical profile is a young patient with painful intramuscular lesion in the extremity causing contractures. The lesion is solid on ultrasound, soft on elastography and shows progressive heterogeneous enhancement along with associated phlebectasia. It is distinct from venous malformations and (solid) hemangiomas. FAVA is a recently described soft-tissue vascular lesion, usually misdiagnosed as venous malformation, mesenchymal tumor, or intramuscular hemangioma. However, the clinico-radiological features can lead one to suspect this uncommon distinct entity. These lesions are mean age refractory to sclerotherapy and embolization; rather, ablation and surgery are the palliative treatments of choice.