[Giant cell tumor of the tendon sheath of the long extensor muscle of the thumb in a 7-year-old child].

The authors report the case of a giant cell tumour of the flexor pollicis longus tendon sheath in a child. This benign tumour, usually observed in women between the ages of 30 to 50 years, has a highly controversial aetiopathogenesis; the existence of initial trauma is found in 50% of cases. The present case concerns a 7-year-old girl with swelling of the right thumb for two years. Surgical resection established the definitive diagnosis by histological examination of the specimen. The follow-up is currently two years, with no local recurrence.