Amylase in lung carcinomas. An ultrastructural and immunohistochemical study of two adenocarcinomas, and a review of the literature.

The ultrastructure of two lung adenocarcinomas with immunohistochemical and biochemical expression of amylase is reported. Isoenzyme determination performed on tumour tissue showed a salivary-type amylase. None of the carcinomas was associated with hyperamylasaemia. Ultrastructurally, the adenocarcinomas contained a varying number of heterogeneous granules resembling lysosomes. None of the tumours contained mature zymogen granules. The findings are discussed in relation to previous cases of amylase-containing lung carcinomas subjected to electron microscopy. The vast majority of these carcinomas were associated with a significant elevation of serum amylase. Various theories which might explain the absence of hyperamylasaemia in the presented cases are proposed. The biological and diagnostic significance of amylase production is discussed.