Clinical History: 
This 64 year old man presented to his primary care physician complaining of hematuria. On MR examination, a mass was found in his left upper groin which was confirmed to be a liposarcoma on subsequent biopsy.

Liposarcoma (well-differentiated)

MR Technique: 
MR images were acquired on a Siemens 3 T Trio Tim MR unit. (A) Coronal pre-contrast turbo spin echo fat-suppressed T2-weighted (TR/TE 4000/81 ms, scan time 3:12 min:sec, slice thickness 5 mm), (B) axial spin echo T1-weighted (TR/TE 612/12 ms, scan time 2:40 min:sec, slice thickness 5 mm), and (C) axial post contrast spin echo fat-suppressed T1-weighted images were obtained.

Imaging Findings:
A complex-appearing, heterogeneously enhancing mass with signal intensity characteristics consistent with fat arises between the adductor brevis and adductor magnus muscles on the left, measuring approximately 11.0 x 6.4 x 8.7 cm. This well-defined, mildly lobulated mass extends superiorly between the obturator internus and externus muscles.