Glucagon and glucagon-like immunoreactive cells in mid- and hindgut carcinoids.

The occurrence of glucagon/glucagon-like immunoreactivity in 31 small intestinal, 34 rectal and 18 appendiceal carcinoids were investigated immunocytochemically using, sequence specific antisera. Glucagon/GLI immunoreactive cells were found in five small-intestinal and five rectal carcinoids, but none were observed in any of the appendiceal carcinoids examined. Glucagon/GLI immunoreactive cells constituted a minor cell population, except in one rectal carcinoid, where most of the tumour cells were of this type. Glucagon/GLI immunoreactive cells were detected with only some sequence-specific antisera, and not with antisera directed against the rest of the glucagon/glicentin molecule. This might indicate that these cells contain a molecule which shares some antigenic binding sites with glucagon/glicentin rather than genuine glucagon/glicentin. It is concluded that this finding contributes to explain why hindgut carcinoids rarely give rise to symptoms related to neuro-endocrine product(s).

Adenocarcinoid of the appendix presenting as bilateral Krukenberg's tumor of the ovaries. Immunohistochemical and ultrastructural studies and literature review.

A patient with an adenocarcinoid of the appendix presented with bilateral Krukenberg's tumors of the ovaries. Immunohistochemical and ultrastructural studies revealed a selective ability of the mucinous (goblet cell) component of the appendiceal neoplasm to metastasize. A review of the literature has revealed nine previously published cases of appendiceal adenocarcinoid metastatic to the ovaries. All showed involvement of both ovaries, but none provided unequivocal evidence of a metastatic proliferating carcinoid element. As the appendiceal lesion is often grossly inconspicuous, it may be overlooked in cases presenting initially with ovarian tumors. Routine appendectomy is therefore recommended in such patients where no grossly obvious primary tumor is evident.

Giant appendicular neurofibroma. A light and immunohistochemical study.

A case of solitary appendicular neurofibromatosis is presented. The neurogenous nature of the lesion was emphasized by the positive reaction for S-100 protein. Attention is directed towards the morphological differences between neurogenous hyperplasia, which is a reactive common place feature in the elderly, and the present example of neoplastic nerve growth, which produced a gigantic appendix. A review of the literature failed to disclose any previous case unassociated with von Recklinghausen's disease.

Argyrophil, non-argentaffin carcinoids of the appendix vermiformis. Immunohistochemical and ultrastructural studies.

Five argyrophil, non-argentaffin classical carcinoids of the appendix were found in 19 appendiceal classical carcinoids and were investigated histochemically, immunohistochemically and ultrastructurally. All tumors consisted entirely of argyrophil cells. Three of the five carcinoids were composed almost totally of peptide YY cells and were negative for serotonin. One of them consisted of peptide YY cells (60%), somatostatin cells (40%), and a few cells with glucagon-like immunoreactivity (GLI). The remaining one without peptides was homogeneously immunoreactive for serotonin alone. Ultrastructurally, each of the four peptide-positive carcinoids was composed of one kind of endocrine cell type with round secretory granules. Average diameter of granules were 150, 160, 190, and 210 nm, respectively. The non-argentaffin, serotonin-positive carcinoid showed predominant round secretory granules and a few irregular ones, both being 150 nm in largest diameter. It is suggested that the argyrophil, non-argentaffin carcinoids of the appendix are subdivided into two groups; carcinoids composed mainly of peptide (especially, peptide YY)-positive cells with round granules of D1 and/or L cell type and those of serotonin-positive cells with pleomorphic granules of ECn cell type.

Immunolocalization of prealbumin as a marker for carcinoid tumours.

Using a PAP immunoperoxidase technique, we have demonstrated the plasma protein prealbumin in 92 (87 per cent) out of a series of 106 carcinoid tumours from various sites. The frequency of detection was greater than with the conventional stains; 83 (78 per cent) of the cases were positive for one or more of these stains. The Grimelius technique was by far the most effective of the conventional stains; it was positive in 81 (76 per cent) cases. We were unable to detect prealbumin in a variety of carcinomas. Although prealbumin identification did not appear to have any advantage over the routine stains in midgut-derived carcinoids, it was much more effective in the diagnosis of bronchial (foregut) and rectal (hindgut) carcinoids. We believe that prealbumin staining offers a cheap, reliable and valuable method for the detection of carcinoid tumours in routine histopathology.

Cytometric study of carcinoid tumors and their metastases.

A series of 5 lung and 11 gastro-entero-pancreatic carcinoid tumors has been studied microspectrophotometrically. All lung carcinoids and the majority of gut-derived tumors had near-diploid stemlines. The DNA absorption profile of metastases was similar to that of primary tumors. There was no difference in DNA patterns of tumors with and without metastases and it is suggested that cytophotometry cannot predict the metastasizing capacity of carcinoid tumors.