Cyst-like lesions of the lunate resembling Kienböck's disease: a case report.

A 33-year-old man presented with a cyst-like lesion of the lunate resembling Kienböck's disease. Radiographs showed collapse of the proximal portion of the lunate and a lucent lesion in the triquetrum. T1-weighted magnetic resonance images showed a low signal in the collapsed part of the lunate but not in the remaining area. During surgery the lesion of the triquetrum contained serous fluid and the lunate was partially collapsed. Histologically, the triquetrum consisted of fibrous connective tissue and the lunate consisted of a mixture of bone, cartilage, and fibrous tissue without necrosis. The lunate lesion was diagnosed as a collapsed cyst-like lesion, although radiographs resembled Kienböck's disease. The lesion was successfully treated surgically with curettage, bone grafting, and external skeletal fixation. The patient is asymptomatic 3.5 years after surgery with some recovery of the trabecular pattern of the lunate.