Tsutomu Koide

Six cases of well-differentiated adenocarcinoma simulating fetal lung tubules in pseudoglandular stage: comparison with pulmonary blastoma

Six cases of well-differentiated adenocarcinoma resembling fetal lung were studied histologically, immunohistochemically, and ultrastructurally, and compared with three cases of pulmonary blastoma. The six cases had no sarcomatous features, unlike the pulmonary blastoma. Individual tumor cells characteristically possessed clear cytoplasm with plentiful glycogen and were similar to the epithelial cells of the branching tubules in the pseudoglandular stage of the fetal lung, as well as the epithelial component of pulmonary blastoma. They also showed little differentiation toward mucous cells and ciliated cells. Although cells containing endocrine-type granules were not found ultrastructurally, a few tumor cells possessed the characteristics of endocrine cells, i.e., cytoplasm was immunohistochemically reactive with anticalcitonin and antigastrin-releasing peptide. Therefore, this type of adenocarcinoma is considered to have a histogenesis similar to that of pulmonary blastoma and may be a tumor with one-sided development of pulmonary blastoma showing only an epithelial component.

Papillary adenoma of type 2 pneumocytes

A case of papillary adenoma of type 2 pneumocytes is reported. A 57-year-old man had an unusual coin lesion in the periphery of the right lung without any symptoms. When detected in a mass survey examination, it was approximately 1.5 cm in diameter, well circumscribed, and located in S4, involving the sixth-order bronchus of B4. Light-microscopic examination revealed cuboidal tumor cells arranged in a papillary pattern. Ultrastructurally, the cells had characteristic osmiophilic lamellar bodies. By immunoperoxidase staining, the tumor cells were shown to have intracytoplasmic surfactant apoproteins. The postoperative course was uneventful, and there is no evidence of disease 8 years later.

Endobronchial polypoid adenocarcinoma of the lung: histological and ultrastructural studies of five cases

Five cases of adenocarcinomas of the lung with predominantly endobronchial polypoid growth in large bronchi were reported. The histology of these cases was well-differentiated papillary adenocarcinoma, the tumor cells of which were columnar (4/5 ) and cuboidal (1/ 5). More than 70% of the volume of each tumor grew in the bronchial lumen with neighboring intraepithelial growth. Ultrastructurally the tumor cells were characterized by numerous mitochondria (5/ 5), some basal bodies (5/ 5), poorly developed cilia (1/ 5), and many dilated smooth endoplasmic reticula near the cell surface (2/ 5); these are features characteristic of ciliated bronchial epithelial cells. There were some mucus-producing cells (3/ 5), which might be differentiating toward goblet cells. Membrane-bound secretory granules with an electron- dense core or fingerprint appearance were also found (2/ 5); these resembled Clara cell granules. The above findings suggested that polypoid adenocarcinoma in large bronchi had the ability to differentiate toward bronchial or bronchiolar surface epithelial cells with or without mucus production.

Peptide hormone production by adenocarcinomas of the lung; its morphologic basis and histogenetic considerations.

The cell source of peptide hormone production and the morphological differentiation were investigated in 18 adenocarcinomas of the lung by immunohistochemistry and/or by electron microscopy. These tumors were found by radioimmunoassay of tumor extracts to contain either one or more of 7 peptide hormones, i.e. adrenocorticotropin (ACTH),β- andγ-melanocyte stimulating hormones (MSH), somatostatin (SS), vasoactive intestinal polypeptide (VIP), gastrin releasing peptide (GRP) and calcitonin(CT). In a combined adeno- and small cell carcinoma, a considerable number of small tumor cells were positively stained for ACTH,β- andγ-MSHS and GRP. In a poorly differentiated adenocarcinoma with mucin and CT production, these products were localized in some single cells. Electron microscopy revealed secretory granules indistinguishable from exocrine or endocrine types. In another mucin-positive adenocarcinoma with high SS and CT contents, some tumor cells were stained for SS and/or CT. Two distinct exocrine and endocrine type secretory granules were found in the same cells. In tumors with 100 ng or less of the peptides/g tissue, most tumor cells were not stained for the peptides but a small number showed proportion of the adenocarcinomas of the lung may show heterogeneous differentiation in both endocrine and exocrine directions.