Iatrogenic disease. Lipoid pneumonia and liver angiosarcoma.

In adults lipoid pneumonia is usually caused by the use of oily nose drops or mineral oil as a laxative. In both cases the oil droplets tend to congregate in the right main bronchus being in a more direct line with the trachea than the left main bronchus. The dorso-lateral segments of the upper lobe are involved if medication is taken before retiring for the night and basal segments in the morning medicators. Lipoid pulmonary masses can be mistaken for carcinoma macroscopically or granulomatous disease such as tuberculosis or sarcoidosis on histology as it provokes a marked fibroblastic reaction with multinucleate giant cells to form granulomas. On CT low attenuation indicates the lipid nature of the 'solid' mass unlike a large bronchial carcinoma. Thorotrast was used in the period 1925-1950 as an intravascular contrast agent particularly for cerebral angiography because of its high density and low immediate toxicity. However, malignant transformation was subsequently recognized as a later complication occurring on average after a latent period of20 years. Angiosarcoma oflymph nodes, spleen and liver occurred as well as cholangiocarcinoma, lymphoma and bronchial carcinoma. Angiosarcomas of the liver are known to be caused by arsenical preparations particularly pesticides and polyvinyl chloride used in the manufacture of plastics as well as by thorotrast. The radiological features ofthorotrast are pathognomonic as it accumulates in the reticuloendothelial system producing an extremely dense spleen, liver and lymph nodes. Malignancy can be diagnosed when the organ becomes less dense, enlarges and contains filling defects. Ascites is a secondary feature of the malignancy.