[Bone tuberculosis of the thumb unmasked by injury].

Tuberculous dactylis is uncommon, which makes it difficult to differentiate from tumorous and metabolic affections. Histological analysis constitutes a reliable and easy way to achieve a positive diagnosis, especially as the bacteriological findings can be negative. We report the case of a 43-year-old woman who consulted for a painful right thumb following an injury. Radiographs showed a fracture of the proximal phalanx through a lytic lesion. Pathology examination of a biopsy specimen revealed granulomata with caseous necrosis, specific to tuberculosis. The clinical signs and radiographs resolved after anti-tuberculosis treatment for 12 months.