49-year-old female with left thigh swelling and pain. A vitamin E marker was placed along the anterior lateral aspect of the thigh, presumably corresponding to the patient's site of swelling. There is a 7.4 x 2.8 x 17.8 cm intramuscular collection along the anterior aspect of the mid and distal femoral diaphysis which displaces the quadriceps musculature anteriorly and laterally. There is associated increased T1 signal abnormality peripherally and within this collection without evidence of significant enhancement on postcontrast sequences. These findings appear most consistent with hematoma formation although superimposed infection cannot be completely excluded by this examination. There is increased signal abnormality within the rectus femoris and vastus musculature on fluid sensitive sequences which is nonspecific but may represent myositis. There is extensive subcutaneous edema along the anterior and lateral aspect of the thigh which is nonspecific. There is also increased signal abnormality within the gracilis muscle at the level of the myotendinous junction with an associated 13 mm lobulated focus of increased signal abnormality on fluid sensitive sequences with peripheral enhancement which may also represent hematoma formation, however, close attention on follow-up examination is recommended to evaluate for interval change (series 14; image 4).There is a moderate size knee joint effusion. No bone marrow signal abnormality is identified. There are foci of susceptibility artifact within the soft tissues along the anterior aspect of the left hemipelvis presumably postsurgical in etiology. There are prominent inguinal lymph nodes
Large collection within the anterolateral aspect of the distal left thigh with the imaging characteristics most consistent with a hematoma. However, a follow-up examination is recommended to evaluate for interval change. There is an additional focus of signal abnormality within the gracilis muscle, as described above, which may also represent a small hematoma which also should be evaluated on a subsequent contrast-enhanced examination. Other findings as described above.