107 A Rare Presentation of a Giant, Multi-Compartmental Lipoma of the Hand Causing Median Nerve Compression

Lipomas are the commonest benign tumour, made up exclusively of adipose tissue, and can arise anywhere in the body. However, giant lipomas of the hand, defined as greater than 5cm in diameter, are rare. They have the potential to invade and cause a multitude of symptoms due to the compression and proximity of underlying structures.

We describe a case of a 64-year-old woman who presents with a swelling of the left thenar eminence, associated with numbness and tingling in all fingers.

MRI and nerve conduction studies confirmed the diagnosis of a lipoma causing median nerve compression. The patient underwent elective surgical excision using a volar approach, with good postoperative recovery. The excised lesion, measuring 12x7x2.4cm, is the largest giant lipoma of the hand reported in literature, and the first to demonstrate invasion from the mid palmar space into both the dorsal sub-aponeurotic space and carpal tunnel.

Space occupying lesions, such as giant lipomas of the hand, are a rare but important secondary cause of compression neuropathies of the upper extremity and must be suspected when these neuropathies present with atypical symptomatology. Any patient presenting with a soft-tissue lesion of the hand demonstrating rapid growth, pain or large size must be thoroughly investigated to rule out malignancy. MRI forms an essential part of the workup in such cases due to its high diagnostic accuracy. Malignant transformation of giant lipomas of the hand is extremely rare, and such lesions can be removed by en bloc marginal resection with excellent postoperative results.