Unusual Location of Intermuscular Lipoma in the thenar eminence: Case Report and Review of the Literature

Abstract

Introduction: Lipomas are the most common benign mesenchymal tumors, typically located in subcutaneous tissue. They can also occur intramuscularly (1-5%) or intermuscularly (0.3-1.9%). Hand lipomas are rare. Case Report: A 53-year-old woman presented with a 2-year history of a painless, enlarging mass in her left hand's thenar region, impairing hand function and grip strength. Physical examination revealed a 5cm, well-defined, painless mass fixed to the deep plan. MRI indicated a benign lipoma. Surgical removal was performed under locoregional anesthesia, and histological analysis confirmed the lipoma diagnosis. Postoperative rehabilitation led to full recovery with no recurrence after 16 months. Discussion: Lipomas, though usually found in subcutaneous tissues of the neck, torso, and limbs, can also develop within muscles, with hand occurrences being particularly rare. Diagnosis is typically confirmed by ultrasound or MRI, which distinguishes lipomas from malignant tumors. Histologically, lipomas consist of mature adipocytes and are often encapsulated. Surgical removal is advised if symptomatic, with recurrence being rare. Conclusion: Hand lipomas, especially intramuscular, are uncommon and can significantly impair function. Accurate diagnosis and careful surgical excision are crucial for effective treatment and preventing recurrence.