Moral-Lavallée lesion: closed degloving injury, less known
Moral-Lavallée lesion is a rare post traumatic soft tissue injury resulting from separation of the skin and subcutaneous tissue from the underlying fascia and creating an underlying blood filled cystic cavity. Several times the lesions are missed during initial examination and become evident after few weeks or months. They may be associated with fractures. Magnetic resonance imaging is the modality of choice for the evaluation of this lesion. It plays a significant role in its diagnosis. The imaging findings would depend on the stage of the lesion. We report three cases of the rare Moral-Lavallée lesion and its imaging characteristics. Case1 A 55 year old gentleman was referred to our institution with a 4month history of pre-patellar swelling. The swelling appeared 2 days after an injury sustained to the knee. He gave a past history of recurrent fall on knee. An MRI was carried out. The imaging findings revealed a well circumscribed T1 weighted hypointense and T2 weighted hyperintense unilocular fluid collection in pre-patellar space, within the subcutaneous tissue. Case2 A 48 year lady came with history of pain and swelling in the lateral aspect of the right thigh since 15 days. She does not recall of any injury. An MRI was called for. The imaging findings revealed a well circumscribed multiloculated mixed intensity lesion on STIR images in lateral aspect of thigh within the subcutaneous tissues appearing hyperintense on T1 weighted images, suggestive of haemorrhage. Case3 A 32 year old man had sustained an injury with a ball on thigh while playing cricket. He initially had pain but continued to play. Later on after being examined he was found to have swelling with ecchymosis in the thigh. The patient had pain on passive knee flexion and hip extension. An MRI was called for. The imaging findings showed a well defined unilocular STIR hyperintense and T1 weighted hypointense lesion lateral aspect of thigh in the subcutaneous tissues superficial to the muscles associated with diffuse subcutaneous and intermuscular edema. STIR hyperintense signal was noted in vastus lateralis muscle suggestive of contusion. Teaching Point Moral-Lavallée lesion is a post traumatic closed degloving injury resulting from the separation of the skin and subcutaneous tissue from the underlying fascia creating a cavity that may fill with blood, lymphatic fluid and necrotic fat. MRI is the modality of choice in its evaluation. It should be among the differentials for any soft tissue lesion associated with shearing trauma. The knowledge of this condition would help in its early diagnosis and management.