Application of light microscopical and ultrastructural immunohistochemistry in the study of goblet cell carcinoid in the appendix

Abstract

Background: Goblet cell carcinoids appear less frequently in the appendix than do other carcinoids. In the presented work a case with a goblet cell carcinoid of the appendix is described.

Methods: Routine histological and histochemical methods were employed, with a combination of histochemistry and immunohistochemistry on one section and light and electron microscopical immunohistochemisty on paraffin-embedded material, were applied to identify the type of the carcinoid and to reveal the fine structure of cell types in the tumour nests of the appendix.

Results: During the biopsy of a patient who had undergone appendectomy, an infiltration with clusters of goblet cells in the submucosa of the appendix was found. After a second operation of right-sided hemicolectomy, similar clusters of goblet cells were detected in the muscle layers of the caecum. After 18 months the patient died from cirrhosis and had not developed metastases or any recurrence. Immunohistochemically the serotonin-, somatostatin-, chromogranin A- and synaptophysin-positive endocrine cells were basally attached to mucin-secreting cells. The combined staining revealed simultaneously present endocrine cells (chromogranin-A-positive) and mucin-secreting cells (PAS- or alcian blue-positive). The ultrastructural immunohistochemistry showed that chromogranin A-positive cells had discoid and pleomorphic granules and were located in tumour nests or as single cells in the appendiceal wall.

Conclusion: The combined histochemical and immunohistochemical procedure and the ultrastructural immunohistochemistry on archival material could contribute in clarifying the diagnosis of goblet cell carcinoid.

Figure 1

Clusters of goblet cells (arrow) infiltrated the muscle layer of the appendix. (Hematoxyllin and eosin). Magnification × 300.

Figure 2

a. Chromogranin A-positive cells (arrows) in the normal appendiceal glands (G) and in submucosa (S), b. Chromogranin A-positive endocrine cells (arrows) delineate the tumour nests of goblet cells, c. Somatostatin-positive endocrine cells (arrows) in the normal appendiceal mucosa, d. Somatostatin-positive cells (arrows) in the appendiceal submucosa (S), e. Synaptophysin-positive endocrine cells (arrow) in the normal appendiceal mucosa, f. Synaptophysin-positive endocrine cells (arrow) in the appendiceal submucosa (S). Magnifications × a, b, c, d, e, f- × 300.

Figure 3

Serotonin-positive endocrine cells in the muscle layer of the caecum. Magnification × 300.

Figure 4

a. PAS-positive mucous cells (pink, star), and brown chromogranin A-positive endocrine cells (arrow) in the normal appendiceal mucosa, b. PAS-positive mucin-secreting cells (pink, star), surrounded by brown chromogranin A-positive endocrine cells (arrow) in a tumour gland in the submucosa, c. Alciane blue-positive mucous cells (blue, star) and brown chromogranin A-positive endocrine cells (arrow) in the normal appendiceal mucosa, d. Alciane blue-positive mucin-secreting cells (blue, star), and brown chromogranin A-positive endocrine cells (arrow) in a tumour gland. (A combined histochemical and immunohistochemical staining). Magnifications a, b, c d × 300.

Figure 5

a. Two chromogranin A-positive endocrine cells (EC) in a tumour gland with discoid and pleomorphic granules, located basally to mucus-secreting cells (M), b. Single chromogranin A-positive endocrine cell (EC), infiltrating the submucosa. Magnifications a × 7000, b × 7 000.