Giant Asymptomatic Intermuscular Lipoma of Right Thigh: Case Report and Review of Literature

Though lipomas are the most common benign soft tissue tumors, giant lipomas are rarely reported in the literature. Giant lipomas should be properly evaluated for any evidence of malignant transformation such as symptomatic, progressive growth in size, heterogeneity, hypervascularity, and irregular septation. Surgical resection should be considered in asymptomatic giant lipomas due to the risk of malignant transformation. Lipomas are the most common benign soft tissue tumors of adipose tissue and are typically small, slow-growing, and asymptomatic. Giant lipomas, defined as lesions measuring ≥ 10 cm in one dimension or weighing ≥ 1 kg, are rare and may mimic malignancy due to their size and deep location. We report a case of a 58-year-old woman who presented with a progressively enlarging, asymptomatic mass over the right thigh for 7 years. Clinical examination revealed a firm mass measuring approximately 20 × 8 cm. Magnetic resonance imaging demonstrated a well-defined, lobulated intermuscular lipomatous lesion measuring 24 × 8.5 × 7 cm involving the vastus medialis muscle, without features suggestive of malignant transformation or neurovascular encasement. Given the progressive enlargement and giant size of the tumor with local mass effect, marginal en-bloc resection was performed through an anteromedial approach. Histopathological examination confirmed a benign encapsulated lipoma composed of mature adipocytes without atypia or malignancy. The postoperative course was uneventful, and no recurrence was noted at the 6-month follow-up. Although most lipomas are managed conservatively, giant lipomas warrant surgical excision for definitive diagnosis, symptom prevention, and exclusion of malignancy. A careful surgical planning, meticulous surgical resection, and close postoperative follow-up can ensure excellent functional outcomes and prevent surgical complications.