Slow-growing buttock mass after failure of incorporation of autologous fat transfer for gluteal augmentation: ultrasound and MRI features.

Gluteal augmentation procedures are gaining popularity and encompass a variety of surgical techniques and methods of graft preparation. While surgical history remains essential for diagnosis, the radiologist must avoid pitfalls and rely on imaging features to recognize both the expected appearance and complications of gluteal augmentation procedures. We report a case of a slowly growing buttock mass after gluteal augmentation with autologous fat transfer 1 year after surgery. The potential diagnostic imaging pitfalls and characteristics on ultrasound and contrast-enhanced MRI are discussed. Multiplicity of fat-containing lesions depicted on large field-of-view images and granulated appearance of the intralesional fat on MRI should allow the radiologist to recognize the appearance of failed fat graft incorporation that can present as a slowly growing encapsulated collection with layered fat and fluid contents.