Right thigh mass Large heterogeneous mass is again seen in the proximal medial right thigh measuring approximately 8 cm TV x 7 cm AP x 8 cm CC. The prior CT measurements likely included portions of muscle fibers due to lack of contrast resolution of non-contrast CT. This appears similar in size to the prior CT when retrospectively re-measured. The mass contains portions of bright T2 signal compatible with cystic changes and portions of high T1 signal with fluid-fluid levels compatible with blood. A definite soft tissue component cannot be excluded. Similar 2-3 cm smaller cystic structures lateral to the proximal femoral diaphysis with high T1 and STIR signal, compatible with blood, likely represent a related process.This mass is located between the pectineus and obturator externus muscles with splaying of the musculature. An intramuscular component cannot be excluded. The vasculature of the right thigh remains separate from this lesion. This lesion abuts the right pubis and ischium without osseous changes evident. This lesion does not extend to the underlying femur. There is mild soft tissue edema at the medial aspect of the proximal right thigh. The visualized intra-abdominal and soft tissue structures are otherwise unremarkable.
Large proximal right thigh mass unchanged in size since 2/12/14. Although IV contrast was not administered, the features of this mass are suggestive of hematoma. Close serial follow up to assess for evolution and resolution is recommended. Ultrasound evaluation for internal vascularity may be helpful to exclude a neoplasm such as synovial sarcoma as a definite soft tissue component to this mass cannot be entirely excluded. 