Mediastinal lipoblastoma with intraspinal extension: MRI demonstration.

Lipoblastomatous lesions are mesenchymal tumors of embryonal white fat and are classified into two forms: a superficial, well-defined mass (lipoblastoma) or a deep, infiltrative lesion (lipoblastomatosis). We report an unique case of mediastinal lipoblastoma in a 17-month-old boy which harbored a dual nature and exhibited the characteristics of both forms, a large well-encapsulated intrathoracic main tumor with focal infiltrative features at the thoracic inlet and transforaminal intraspinal extension forming a long-segment extradural mass. In addition to specific signal characterization of a fatty mediastinal mass with intratumoral streaks and whorls corresponding to the fibrovascular network, magnetic resonance (MR) imaging offered clear demonstration of the chest wall, lower neck and intraspinal extension, which was important for preoperative planning.