Pseudotumours due to oil palm thorn injury.

Three cases are reported in which pseudotumours developed in the hand following injury by oil palm thorns. In one patient there was a periosteal reaction of the proximal phalanx adjoining the site of injury. The lesions were excised, and the embedded oil palm thorn was identified in all three. The clinical and pathological features of the lesions and problems in their diagnosis are described. In every case the local tissue reaction was out of proportion to the size of the foreign body, raising the possibility that a toxic substance might have been released by the thorn.