Cases reported • Apudoma

11/17. Ectopic ACTH syndrome in APUD tumors.

Rapidly progressing hypercorticism was observed in 2 patients with malignant neoplasms, a 72-year-old man with anaplastic small cell carcinoma and a 48-year-old woman with a primary apudoma of the liver. Both patients were treated with chemotherapy in conventional doses. Both patients developed acute dyspnea and sudden death, 7 and 10 days, respectively, after chemotherapy was given. The possibility that patients with ectopic adrenocorticotropic hormone (ACTH) secretion are excessively vulnerable to chemotherapy is raised and judicious management urged.

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12/17. Malignant apudoma of the liver with symptomatic intractable hypoglycemia.

This report documents a case of a fatal primary malignant neoplasm of the liver with metastases to the lymph nodes of the porta hepatis and the pubic bone. Profound, intractable hypoglycemia was seen during the course of the disease. No immunoassayable insulin was found in the blood during episodes of severe, symptomatic hypoglycemia. The neoplasm was composed of uniform polygonal cells with distinct cytoplasmic borders growing in broad strands with a tendency toward nesting and was morphologically similar to neoplasms of neural crest derivation. The presence of osmophilic, membrane-bound granules in the neoplastic cells was documented by ultrastructural studies. The tentative conclusion that the hypoglycemia was produced by the secretion of a substance with insulin-like activity, probably a polypeptide, by the secretory granules in the neoplastic cells is supported by clinical and laboratory data.

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13/17. Gastrin-secreting tumor of the duodenum (G-cell apudoma) associated with secondary biliary cirrhosis.

A middle-aged woman with evidence of chronic cholestasis of several years and no previous abdominal surgery was initially thought to have primary biliary cirrhosis. Clinical evaluation disclosed a well-developed secondary biliary cirrhosis apparently caused by extrahepatic obstruction due to a 1 X 2 cm neoplasm of the periampullary duodenum. Electron microscopy and immunofluorescent studies showed the neoplasm to be a G-cell adenoma. Wide local excision has resolved the biliary obstruction. Bening or slow-growing duodenal tumors, if they involve the ampulla of vater, may produce prolonged partial extrahepatic obstruction and secondary biliary cirrhosis.

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14/17. Pancreatic-polypeptide-producing apudoma of the liver.

A large hepatic excised from a 62-year-old man resembled a carcinoid tumor. No endocrine syndrome was present and an alternative primary source of tumor was found, despite an intensive search. The tumor cells were classified according to the type of electron-dense granules present: ACTH, gastrin (G), bombesin (P), and pancreatic polypeptide (PP) type granules were identified. Immunofluorescent staining with antibodies to several polypeptide hormones detected PP-containing tumor cells only. This rare tumor is therefore a PP-apudoma; possibly of intrahepatic bile duct origin.

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15/17. Neuroendocrine neoplasms in unusual primary sites.

Primary neoplasms arising in the liver (3 cases), skin (3 cases) and larynx (2 cases) were studied with a combination of light microscopy, immunohistochemical and electron microscopic techniques. Clinically, only one case exhibited a hormonal syndrome (Zollinger-Ellison) while another had elevated levels of calcitonin in the serum. By light microscopy only one tumour appeared characteristically neuroendocrine ('carcinoid'). The other cases showed variable patterns of small to intermediate size cell carcinomas at times admixed with exocrine appearing areas. Immunoperoxidase studies showed reactivity for various peptides including gastrin, calcitonin, somatostatin and ACTH. Several tumours were positive for more than one peptide. Electron microscopy revealed variable populations of neurosecretory type granules either in the main cytoplasmic mass or in cytoplasmic processes. We conclude that some 'undifferentiated' neoplasms from the aforementioned sites may prove to have neuroendocrine differentiation if the proper techniques are applied to their study. Clinical hormonal syndromes appear to be rare in these tumours;s however, determination of various amine and/or peptide materials, or possibly their metabolites, may be valid aids for their recognition and monitoring. The structural patterns of these tumours are very variable and may include cells with squamous features as well as exocrine differentiation with occasionally prominent production of mucosubstances.

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16/17. A cutaneous apudoma or Merkel cell tumor? A morphologically recognizable tumor with a biological and histological malignant aspect in contrast with its clinical behavior.

Clinical, microscopic, ultrastructural, and histochemical characteristics of a primary cutaneous tumor, identified as an apudoma possibly arising from merkel cells, are presented. The tumor can be diagnosed by means of routine histology. In some cases the argyrophylic staining technique can be helpful. The dermatological and histological aspects of this tumor suggest a highly malignant undifferentiated process. The biological behavior of this tumor, however seems to be of a low-grade malignancy. It is therefore important to recognize it from undifferentiated, highly malignant, mostly metastatic processes in the skin. There is also a summary of the clinical history and microscopic findings of identical tumors in 4 other patients.

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17/17. Metastasizing neuroendocrine tumor of unknown origin found in cervical lymph nodes: a case report.

neuroendocrine tumors are a diverse category of tumors that have been known to produce biologically active amines and ectopic hormones of various types. Numerous metastasizing primary lesions have been identified, however, the head and neck region is not a common site for them. Even less common than these are head and neck metastatic sites without an identifiable primary lesion. We report a case of a metastatic neuroendocrine tumor, where the primary site eluded detection despite an extensive battery of investigations.

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