Carcinoid tumor of the vermiform appendix with Cushing's syndrome.Ultrastructural study of a case

Abstract

A young woman with Cushing's syndrome recovered after removal of an appendiceal carcinoid tumor which contained ACTH in excess. The tumor was not associated with any features suggestive of serotonin production although the neoplastic cells were argyrophilic and demonstrated a positive argentaffin reaction. The cells contained pleomorphic dense granules and had other cytoplasmic characteristics of the enterochromaffin or argentaffin cells that are typically found in midgut derivatives. They displayed 4 ultrastructural features of polypeptide hormone‐producing cells which are a high content of free ribosomes, low levels of rough endoplasmic reticulum, electron dense mitochondria, and membrane‐bound secretion vesicles. However, they lacked one important ultrastructural feature of such cells, namely high levels of smooth endoplasmic reticulum in the form of vesicles. A sixth ultrastructural characteristic of polypeptide hormone‐secreting cells, fixation lability of mitochondria, could not be assessed from the material available for study.

Surgical treatment of malignant carcinoid tumours of the appendix

“…The symptoms of carcinoid syndrome are rare but may be indicative of liver metastases (23,24). Haematological, biochemical, urinary investigations are then required to complement computerised tomography, or magnetic resonance imaging and radionucleotide scintigraphy to confirm carcinoid syndrome (25,26).…”

Adenocarcinoid of the Appendix Presenting as a Disseminated Ovarian Carcinoma: Report of a Case

“…Carcinoid syndrome or Cushing's-like syndrome, resulting from the systemic effects of peptide secretion, are extremely rare complications of an appendiceal carcinoid, and indicate liver metastasis. 7,8 Seventy percent of carcinoid tumors are situated at the tip of the appendix and less than 10% are found in the base of the organ. 3 The adenocarcinoid arises in the base of the mucosa, and diffusely infiltrates the submucosa and the muscularis of the appendix without forming a distinct mass or a conspicuous mucosal lesion.…”

Recovery from severe osteoporosis following cure from ectopic ACTH syndrome caused by an appendix carcinoid

“…Among carcinoids, it is most commonly the bronchial or thymic carcinoids, and only rarely carcinoids of other locations, that cause the ectopic ACTH syndrome. A literature search over the last 30 years revealed three reports in which the appendix was the proven source of ectopic ACTH secretion [15][16][17]. In two cases, the carcinoids of the appendix were also incidentally found during laparatomy [15,16], and in one, metastases of the liver caused the syndrome 9 years after removal of the primary tumour by appendectomy [17].…”

“…A literature search over the last 30 years revealed three reports in which the appendix was the proven source of ectopic ACTH secretion [15][16][17]. In two cases, the carcinoids of the appendix were also incidentally found during laparatomy [15,16], and in one, metastases of the liver caused the syndrome 9 years after removal of the primary tumour by appendectomy [17]. Until recently, it was thought that carcinoids of the midgut region do not cause the ectopic ACTH syndrome [18] and they are not included in the list of possible ectopic ACTH sources by major textbooks of endocrinology.…”