Pseudo-adrenal incidentaloma: magnetic resonance imaging in a patient with para-adrenal Castleman's disease.

We report a case of para-adrenal angiofollicular lymph node hyperplasia (Castleman's disease) of the hyaline-vascular type. The mass could not be differentiated from an adrenal tumor by ultrasonography and computed axial tomography (CT). However, magnetic resonance imaging (MRI) suggested the possibility of an extra-adrenal origin of the mass. The intensity of the mass by MRI was homogeneous and of a higher intensity in the T2-weighted image than in the T1-weighted image, a finding similar to lymphadenopathy, lymphatic tumorous mass or metastatic tumor of the lymph node. Ultrasonography, CT and MRI may not be useful in characterizing Castleman's disease, but MRI was useful to distinguish asymptomatic para-adrenal masses from those of adrenal origin.