Insufficiency fracture of the clavicle after neck dissection: imaging features.

Insufficiency fracture of the clavicle is a rare complication that can occur in patients who have undergone neck dissection. The differential diagnoses of this entity include recurrent metastatic disease, post-radiation sarcoma, trauma, and infection. We reviewed the images of seven lesions in six patients who had undergone neck surgery and had stress fractures of the clavicle without tumor metastasis. All lesions involved clavicular fractures and had mass formation around the bone fracture. Two lesions mainly comprised sternoclavicular joint (SCJ) surface destruction, and six mainly comprised fractures of the proximal end of the clavicle. Five (71%) had increased clavicular bone density. Six lesions (86%) had fluid collection in the SCJ, and three of these lesions (in two patients) were complicated by infection. fluorodeoxyglucose-positron emission tomography (FDG-PET) showed relatively weak uptake (SUVmax 0.96-3.09).