Intraosseous lipoma of the clavicle with extraosseous extension.

Intraosseous lipomas are rare primary benign bone tumors which present with highly nonspecific radiographic features that may lead to equivocal diagnoses. Advanced imaging studies such as MRI with and without contrast and, in some selected cases, tissue sample analyses are required in the diagnostic pathway. Here we describe the second case in the literature of an intraosseous lipoma of the clavicle and the first with extraosseous extension. Subsequent to histologic confirmation the lesion was monitored with clinical and radiologic evaluation.