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Clinically, soft tissue contusions due to trauma are common and often resolve spontaneously if the condition is not severe. But sometimes after a few days or even years after trauma, the patient's pain has not subsided, or even more serious, imaging examination found abnormal mass, can not be characterized as a simple contusion, how to diagnose?
Case 1:
Basic history: 44-year-old female with chronic left hip pain. The patient's oral vague recollection of traumatic injuries to the left hip long ago. MrI of the left hip is shown below.
Fig. 1-1: T1WI diagram of the left hip axis shows a class of circular abnormal signal clumps seen in the lateral soft tissue of the proximal femur, with uneven internal signals (shown by yellow arrows)
Fig. 1-2: Left hip axis STIR sequence showing several high-signal foci distributed in this mass with low signal (shown by arrows)
Figure 1-3: Left hip coronal STIR sequence showing several very high signal foci within a low-signal mass (shown by arrows)
Case 2:
Basic medical history: 39-year-old paraglider, swollen and painful right thigh and pelvis after an accident trauma.
Figure 2: The right hip coronal T1WI and STIR sequences show a huge subcutaneous mass on the lateral thigh on the right side, showing a low T1 signal, a HIGH SIGNAL OF STIR (indicated by the red arrow), a clear boundary, and a fat signal (indicated by the arrow) in it. Lesions are located on the surface of the broad fascial tension muscle (T), external femoral muscle (V), and rectus femoris muscle group
Case 3:
Basic medical history: male, 52 years old, traffic accident. Ct and MRI test results are as follows.
Fig. 3-1: CT examination of hip joint and femur found abnormal low density aggregation in the right subcutaneous soft tissue, and adjacent muscle tissue was compressed; coronal position (C figure) could see the abnormal density of the strip of fat density shadow
Figure 3-2: The coronary magnetic resonance T1WI and T2WI sequences show that the corresponding position is a long T1 long T2 anomaly signal
Case 4:
Basic medical history: male, 30 years old, with a history of trauma a few months ago.
Fig. 4: Right hip MRI examination is coronary T1WI sequence, axial T2WI sequence and coronal STIR sequence can be seen in the right side of the subcutaneous broad fascia tension muscle lateral soft tissue short T1 long T2 abnormal signal mass, STIR shows a significantly high signal, the liquid level is visible inside
If you encounter the above situation, how to diagnose it?
Diagnosis of lesions: Morel-Lavallée injury.
Morel-Lavallée injuries were first described by the French physician Morel-Lavallée in 1863 as soft-tissue detachments, in which the skin, subcutaneous tissues and fascia are stripped to form a closed space, and bloody or lymphatic fluid accumulates in the cavity. It tends to occur in the large thick femur and proximal thighs.
1. Damage mechanism
Shear violence acts directly on parts of the body, resulting in the separation of the skin, subcutaneous tissue and deep fascia tissue, forming a soft tissue closure latent detachment injury, bloody or lymphatic fluid accumulation cavity, often accompanied by adipose tissue mixed in.
Figure 5: Schematic diagram of the damage mechanism shown
2. Imaging characteristics
(1) Lesions are mostly located between the deep subcutaneous fat and the deep fascia.
(2) The different imaging density and signal are mainly related to the different components and contents of fibrous tissue, lymphoid tissue and blood inside the lesion: the acute and subacute phases are mostly bloody components; the chronic phase is dominated by liquid signals.
(3) Strips of fat signaling can often be seen inside the lesion, and some can be seen with liquid level and lipid level.
3. Treatment
Conservative treatment of this injury is often ineffective, and common treatment methods include MRI-guided puncture therapy, doxycycline-induced occlusion of the cystic cavity, and surgical resection.
4. Summary
Abnormal density/signal clumps between deep subcutaneous fat and deep fascia in the large tuberosity of the femur and proximal thighs, where fat density/signal foci may be seen with a history of trauma, the possibility of Morel-Lavallée injury is to be thought of. Morel-Lavallée injuries are easily misdiagnosed early as common soft tissue injuries, affecting treatment outcomes and prognosis.
Source 丨Xinxiang medical imaging
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