Giant lipoma of thigh – Case report of rare tumour

Abstract

Lipomas are tumours which arise from fat tissues and are most common soft tissue tumours. When lipomas turn malignant, they are known as liposarcoma. Lipomas of length greater than 10cm or weight greater than 1000 grams is defined as giant lipoma. Lipomas are mostly asymptomatic at presentation, however when enlarged they can cause symptoms like pain, difficulty in walking due to compression of underlying neurovascular structures. A male patient aged 65 years presented with non-painful swelling in the left thigh which gradually increased in size over last 6 months. The patient did not have any symptoms due to swelling. On examination the swelling was measured 20x15 cm not fixed to skin or underlying bone or soft tissues. No inguinal lymph node was palpable. Contrast Enhanced Magnetic Resonance Imaging (CEMRI) of thigh showed a well circumscribed fat enhanced lesion in the anterior compartment of the left thigh which measures approximately 10.4 x 12.5 x 21.4 cm. The mass lesion was abutting & medially displacing the femoral neurovascular bundle without encasement. Core biopsy from lesion showed adipocytes with background myxoid stromal and skeletal tissue. No cellular pleomorphism mitosis or increased vascularity is evident. Patient underwent excision of tumour with intact capsule under GA via longitudinal elliptical incision. Final histopathology was reported as mature adipocyte separated by thin fibrous septa suggestive of lipoma without any evidence of lipoblasts or atypical nuclear cells. Patient does not have any recurrence after one year of follow up. Surgical excision with intact capsule is treatment of choice for lipoma. In giant lipomas malignant transformation to liposarcoma should be suspected. On imaging malignant transformation is suspected with characteristics like solid component, haemorrhage, infiltration into neurovascular structures which is confirmed on final histopathology report after excision.