Xanthomatous pseudotumor of lung. A case report with electron microscope and lipid studies

A large benign xanthomatous pseudotumor, 10 cm in diameter, was successfully removed from the lung of a 5 1/2-year-old girl. The exact nature of this unusual lesion was not known but light and electron microscopy and lipid analyses suggested either a chronic inflammatory lesion in which mast cells were prominent or a benign tumor arising from poorly differentiated neuronal elements in the lung.