Acta Medica Medianae (Mar 2012)
NEW CLASSIFICATION AND DIAGNOSIS OF APPENDICEAL CARCINOID TUMORS
Abstract
Carcinoid tumours are rare lesions that belong to the APUDoma category having the capacity of Amine Precursor Uptake and Decarboxylase. Gastrointestinal system comprises 90% of all carcinoids in the body and they are the most common type of primary malignant lesions of the appendix. New WHO classification of gastrointestinal carcinoids, diagnostic dilemmas of some carcinoid variants and, sometimes unpredictable prognosis are the reasons for the following study: clinical, macro- and microscopical as well as cytochemical and immunocytochemical examination of the vermiform appendix carcinoids, surgically removed from 16 patients. The appendectomy was induced by acute appendicitis or tumorous mass, without carcinoid syndrome. After two-day fixation in 10% formaldehyde, routinelly processed and embedded in paraffin, laboratory sections were stained with H&E, Fontana-Masson’s, Grimelius’, FIF and ABPAS methods. ABC method has been used for immunohistochemical examination. The antibodies for Chromogranin A, NSE, Synaptophysin, Cytokeratin 7, S-100 protein, Ki67 and CEA (primary antibodies) and ABC (secondary antibody) (Dako Kopenhagen) were tested. The patients had no carcinoid syndrome. The most frequent was classic appendiceal carcinoid, well differentiated - NETG1 (8 cases), without metastases; goblet cell carcinoids were rare (3 cases), one case with liver metastases. The second case of goblet cell carcinoid was associated with cystadenoma papillare mucinosum, complicated by pseudomixoma peritonei and the third case was limited only to appendiceal wall. The patient with liver metastases died five months after appendectomy. The patient with goblet cell carcinoid associated with papillary mucinous cystadenoma and complicated by pseudomixoma peritonei had re-operation with both partial cecal and right ovarial resection, associated with washing the peritoneal cavity. The patient was feeling well during six years from the second operation. Based on our results, we have concluded that: the prognosis of the appendiceal carcinoids depends on the stage of the disease in which the carcinoid was discovered; classic carcinoids had the best prognosis, as well as argentaffin and argyrophyl positive characteristics; goblet cell carcinoids have amphicrine characteristics: AB-PAS and argyrophil positive granules, but often, the granules are weakly or argentaffin negative. Tubular carcinoid must be differentiated immunohistochemically from metastatic adenocarcinoma that have the worse prognosis than these carcinoids.
