Morell-Lavallée Lesion(MLL) in Right Thigh: Case Report

Introduction: Morell-Lavallée lesions is traumatic separation leading the skin to separate fromthe subcutaneous tissue of the underlying muscular fascia. Such separations lead rupture of smallperforating vessels in this region, resulting in the formation of cavity that may be filled withblood, lymph, fat foci and sometimes necrotic materials [1,2]. Morel-Lavallée lesion first describedin the lateral aspect of the proximal thigh, which is the most common site of this lesion, howeverother sites such as like greater trochanter, lower back, knee and scapula have been described [3,4].In the present article, we describe case of Morell-Lavallée lesion of thigh in 73 years old male.Case History: 73 years old male presented with swelling in right thigh from eight years ago. Theswelling was gradually progressive in size during five months ago. It is not associated with pain,fever and discharge and there is no weight loss or loss of appetite. He met an accident leads to hipdislocation and fracture in leg in past history. There is no anticoagulant therapy in medication.Physical examination reveals swelling in the thigh measuring 14 cm in greater dimension. Theswelling was globular in shape with smooth surface with no tenderness and local rise in temperatureand and shows cystic feature on physical examination. Soft tissue ultrasonography revealed an ovalshape mass like lesion of 115×52×65 mm which is non-vascular in color mode. It is 12 mm awayfrom skin surface. MRI revealed very well encapsulated oval or fusiform mass like lesion of 10×5×5 cm size within subcutaneous fatty tissue of lateral aspect of right thigh, the lesion issituated over fascia between skin and underlying muscle, containing fluid-fluid level with upperfluid content of high signal intensity in PDFS sequence and lower fluid content of moderate signalintensity in both T1 weighted and T2 weighted sequence containing some debris and some muralnodules, after injection of contrast no enhancement is demonstrable in different parts of this lesioneither in its wall or in internal solid appearing components and mural nodules. Patient supposed tobe undergone surgical excision, he underwent surgical exploration and removal of this cysticformation. Gross exam shows one grayish tissue fragment measuring 14×8×4.5 cm which has cysticappearance with maximum diameter of 13 cm and contains necrotic and granular brown materials.Staining with hematoxylin and eosin was done. Histologically, tumor shows cystic lesion whichcontain necrotic and also eosinophilic amorphous material lined by fibrofatty tissue, hemosiderinladen macrophage and foamy histiocytes. Proliferative vascular channel and cholesterol clefts arealso noted. All margins show fibrofatty tissue and some contain muscular tissue and only lateralmargin shows necrotic debris. Histologic and also imaging and clinical findings compatible withmoral lavallee lesion. No evidence of malignancy or sarcoma in this specimen.Discussion: Morel Lavallee lesion is cystic lesion caused by blunt injury and especially indegloving injuries. The subcutaneous tissue is torn away from the relatively firm underlying musclefascia by tangential shear forces. This leads to create potential space which is filled with blood,lymph and nerotic debris from the disrupted perforating vessels and capillaries [5]. Morel Lavalleelesions are more seen over the trochanteric region or anterolateral of thigh; other locations alsoreported such as the lower lumbar region, calf and gluteal region [2]. The creation mechanism ofthis lesion is not completely clear yet as it represents rare entity. But some steps of the processhave been identified; the initial formation of the potential blood-filled space, there is evolution ofthis haematoma with absorption of the blood, which replaced by serosanguineous fluid [6]. The laststep in key steps of events is the formation of peripheral fibrous capsule as anti-inflammatoryreaction. The entrapment of fluid within the cyst may lead to degree of chronic inflammation thatmay cause the enlargement of the lesion over the time [3]. The differential for Morel-Lavalléelesion include posttraumatic fat necrosis, coagulopathy-related hematoma, and posttraumatic earlystage myositis ossificans [7]. It may be misdiagnosis with sinister condition like sarcoma.Treatments have range from percutaneous drainage to surgical excisions [7,8 Conclusion: We presented the rare case of Morel Lavallee lesion of thigh. MRI is the bestimaging modality for diagnosis of Morel Lavallee lesions. Treatments have range frompercutaneous drainage to surgical excisions. Surgical excision is the preferable treatment modalitywhen the lesion is long standing or includes large volume of fluid. It is important to diagnosis theMorel Lavallee lesion from other differential diagnosis specially sinister conditions like soft tissuesarcoma. So, attention to history, clinical examination and imaging is very important.