Solid Aneurysmal Bone Cyst of the Metacarpal Bone Differential Diagnosis and Therapeutic Consequences

Background: A solid aneurysmal bone cyst is a rare tumor-like lesion of bone. As conventional aneurysmal bone cyst it is a benign, although locally destructive lesion. While the aneurysmal bone cyst is characterized by cyst-like walls of predominantly fibrous tissue filled with free-floating blood, the solid variant shows essential findings identical to those seen in the walls of conventional aneurysmal bone cysts, except that the lesion almost completely lacks the blood-filled spaces and the cyst walls. Differential Diagnosis: Aneurysmal bone cysts and solid aneurysmal bone cysts may easily be mistaken for a malignant tumor, both radiologically and histologically, due to their great rate of growth, tremendous destruction of bone, and marked cellular exuberance in the early to mid phase of development. Case Study: A case of solid aneurysmal bone cyst of the fourth metacarpal is presented. In spite of the relatively unusual location it allows to clearly demonstrate both, the task of correct differential diagnosis and the surgical spectrum of therapy including local recurrence.