Case report: chondromyxoid fibroma arising at the clavicular diaphysis.

This report presents an extremely rare case of chondromyxoid fibroma arising at the clavicle. To the best of our knowledge, this may be the first case report demonstrating in detail the clinicopathological findings of chondromyxoid fibroma at the clavicle. The patient was a 34-year-old housewife. Radiography and CT demonstrated an osteolytic lesion with cortical thinning and expansion with partial destruction at the diaphysis of the left clavicle. MRI showed a homogeneous iso-signal intensity mass in T1-weighted imaging and a heterogeneous high-signal intensity in T2-weighted imaging. Histological findings of the widely resected tumor were consistent with chondromyxoid fibroma. The pre-operative diagnosis of chondromyxoid fibroma at an unusual location, as in this case, is difficult from the imaging examinations, or sometimes even from the histological examination of biopsy materials.