Heterozygous familial hypercholesterolemia: detection of xanthomas in the Achilles tendon with US

Prospective sonographic evaluation of 44 Achilles tendons in 22 patients with heterozygous familial hypercholesterolemia (FH) was performed with linear-array transducers with high frequency and high resolution. Intratendinous hypoechoic regions believed to represent xanthomas, ranging from single hypoechoic nodules to diffusely enlarged tendons that were heterogeneously hypoechoic, were seen in 40 of the 44 tendons (91%) and 21 of the 22 patients (95%). In addition, focal xanthomas were seen in two of three patients whose Achilles tendons were either normal or questionably abnormal at palpation. The direct visualization of xanthomas in most of these patients contrasts with findings from previously published studies, in which sonographically detected involvement was based on secondary tendon enlargement alone. The improved sonographic visualization of tendon xanthomas in FH, rather than the secondary tendon enlargement caused by them, therefore, suggests a new role for ultrasound in the early diagnosis and follow-up of these cases.