Intravascular lymphomatosis presenting in the lung

We report four patients who had intravascular lymphomatosis (IVL) that presented as interstitial lung disease. All four patients had progressive shortness of breath, weight loss, fever, and diffuse interstitial infiltrates on chest radiographs. Open lung biopsy samples showed an interstitial pneumonia except for the intravascular proliferation of large lymphoid cells associated with irregular congestion, fibrin microthrombi, and intimal proliferation in vessels. This appearance corresponded to an intravascular large cell lymphoma (malignant angioendotheliomatosis [MAE], angiotropic lymphoma). The differential diagnosis of IVL with other pulmonary lymphoproliferations and intravascular malignancies is reported.