Ganglion cyst of the proximal tibiofibular joint causing foot drop-diagnostic problem of differentiating from neuritic leprosy.

A six-year old boy presented with pain around the knee joint and abnormal gait of one month duration. There was no history of hypopigmented anaesthetic patches, neuritis or family history of leprosy. Clinical examination revealed a localized cystic swelling of 1 x 1 cm in size in the region of left common peroneal nerve, with sensory loss on the lateral aspect of the left leg which was mistaken for a nerve abscess.