Lung, Talc granulomata

The haematoxylin and eosin stain (left) in this photomicrograph demonstrates a section of lung parenchyma involved by multiple perivascular granulomata. Under polarized light microscopy (right), the presence of polarizing foreign material is demonstrated in these granulomata. This histologic appearance is characteristic of talc granulomata, which occur in the lung as a result of intravenous use of drugs, such as heroin, which are meant for oral use. The non-soluble filler material included in the injected solution accumulates in the lung, in the classic perivascular distribution, inducing a granulomatous tissue response, which can be associated with various degrees of fibrosis and chronic inflammation. Clinically, these lesions can be picked up on imaging when a patient presents with respiratory symptoms, most often due to a co-existing infection; they can also present as incidental findings, either on imaging or at autopsy.