[Lipoma responsible for tarsal tunnel syndrome. Apropos of 2 cases]

Two cases of tarsal tunnel syndrome caused by lipoma are reported. Both patients had ankle pain that radiated to the sole for years. On physical examination, localized swelling behind medial malleolus was found. Tinel's sign was provoked by gentle percussion on the posterior tibial nerve and its branches. Electrophysiological study showed fibrillation in foot intrinsic muscles or prolongation of motor and sensory latency of plantar nerves. Computed tomography of the tarsal tunnel demonstrated areas of low density indicating masses of high lipid content. Exploration of tarsal tunnel revealed compression of the medial plantar nerve by a lipoma. After excision of the lipoma, both patients had complete relief of ankle and foot pain. Computed tomography is helpful in delineating the nature and extent of lipoma within the tarsal tunnel.