February 21, 2012

Soft Tissue Lipoma

A longitudinal ultrasound image of the back (behind the scapula) shows a well-circumscribed, oval, solid mass (arrows) with internal slight hyperechogenicity superficial to the deep muscle.

Facts: Soft Tissue Lipoma
  • Very common mesenchymal tumors
  • May be palpable, painless, soft and mobile on clinical examination
  • May be multiple in up to 5% of cases
  • Common in patients older than 50 years
US Findings
  • Classic lipomas are hyperechoic and homogeneous (compared with muscle) with well-defined borders
  • Sonographic appearance may depend on internal cellularity (amount of fat and water in the lesion). Lesions with pure fat are hypo- or anechoic but those with mixed fat/water are quite echogenic
  • Appearance highly variable from hyper-, iso-, hypoechoic or mixed echoic and bordes can be circumscribed or poorly defined
  • It can be difficult to confidently diagnose lipoma on US, accounting for variable US features and high interobserver variability on description of lesions.

Our case: soft tissue lipoma proven by histopathology


Inampudi P, Jacobson JA, Fessell DP, et al. Soft-tissue lipomas: accuracy of sonography in diagnosis with pathologic correlation. Radiology 2004;233:763-767.

February 11, 2012

Hepatic Hemangioma: MR Findings

Axial MR images show a large left hepatic lobe mass that has a very high T2 signal intensity and peripheral nodular contrast enhancement and incomplete delayed fill-in.

  • Most common benign hepatic tumor
  • Female:male ratio = 2:1 to 5:1
  • Most are asymptomatic and found incidentally on imaging exams
  • US, CT, MRI and nuclear medicine scan may demonstrate hemangioma
  • Routine MR protocol for characterizing liver lesions = T1, FSE T2 (with fat suppression), dynamic gadolinium enhancement
MR Imaging Findings
  • A mass with T1 hypointensity, strong T2 hyperintensity with a "light bulb" pattern on heavily T2W sequence
  • Dynamic enhancement shows peripheral nodular enhancement (the nodules do not contact each other) with progressive centripetal enhancement. The inner ring of the enhancement is undulating.
  • Washout phase: persistent homogeneous enhancement without heterogeneous or peripheral washout
  • Small lesions may demonstrate homogeneous arterial enhancement but the enhancement will be persistent and homogeneous in washout phase.
Lencioni R, Cioni D, Iartolozzi C. Focal liver lesions: detection, characterization, ablation. 2005