Prevalence of lymphocytic infiltrate in 1400 pituitary adenomas.

To evaluate the prevalence of lymphocytic infiltrate in a large series of pituitary adenomas, we retrospectively studied tumor tissues from 1400 patients. Based on immunocytochemical data, tumors were classified as PRL (n=411), multihormonal (n=310), immunonegative (n=275), ACTH (n=166), GH (n=137), alpha subunit (n=44), FSH and/or LH, (n=42), and TSH (n=15) adenomas. The lymphocytic infiltrate was diagnosed on histological examination and investigated by immunostaining with anti LCA (human leucocyte common antigen), anti CD45RO (human T cell) and anti CD20 (human B cell) antibodies.

Interactions between normal and tumoral tissues at the boundary of human anterior pituitary adenomas. An immunohistochemical study.

We studied the boundary between adenoma and peritumoral anterior pituitary tissues in order to understand their mutual interactions during tumour progression. We selected 18 adenomas of different secretory type, grade and invasiveness in which fragments of peritumoral anterior pituitary were still attached to the adenoma. Immunohistochemistry was performed on serial sections with markers of the basement membranes (type IV collagen), the hormone-producing cells of the normal and neoplastic anterior pituitary, and the folliculo-stellate cells (S-100 protein).

Somatostatin cells in human somatotropic adenomas.

Data from our group have shown that the human adenomatous and normal anterior pituitary may be the source of somatostatin (SRIH). SRIH-producing cells were identified in two somatotropic adenomas. Immunoreactive SRIH cells were present in both cases.

Specific alterations of the basement membrane and stroma antigens in human pituitary tumours in comparison with the normal anterior pituitary. An immunocytochemical study.

Our report is the first immunocytochemical study of the principal elements of the basement membrane (BM) and connective tissue in normal and adenomatous human anterior pituitaries. In normal tissues, both the parenchymatous BM limiting the endocrine cell cords and the endothelial BM around the capillaries were continuous and were stained with anti-laminin (LM), anti-type IV collagen (CIV) and anti-fibronectin (FN) antisera. Antiserum to type I collagen (CI) stained the connective tissue only.