PubMed · 13109421
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E G BOVILL, E H ROBERTS. 1953. Rectal carcinoids.. https://pubmed.ncbi.nlm.nih.gov/13109421/
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The pathobiology of neuroendocrine tumors (NETs) is hampered by the lack of scientific tools that define their mechanisms of secretion, proliferation, and metastasis; and, currently, there are no accurate means to assess tumor behavior and disease prognosis. Molecular biologic techniques and genetic analysis may facilitate the delineation of the molecular pathology of NETs and provide novel insights into their cellular mechanisms. The current status and recent advances in assessment of the molecular basis of tumorigenesis of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) were reviewed (1981-2004). The objectives of this retrospective study were to provide a cohesive overview of the current state of knowledge and to develop a molecular understanding of these rare tumor entities to facilitate the establishment of therapeutic targets and rational management strategies. Multiple differences in chromosomal aberration patterns were noted between gastrointestinal (GI) neuroendocrine and pancreatic endocrine tumors (PETs). Divergence in gene expression patterns in the development of GI carcinoids and PETs was identified, whereas examination of the PET and GI carcinoid data demonstrated only few areas of overlap in the accumulation of genetic aberrations. These data suggest that the recent World Health Organization classification of GEP-NETs may require updating. In addition, previous assumptions of tumor similarity (pancreatic vs. GI) may be unfounded when they are examined at a molecular level. On the basis of the evolution of genetic information, enteric neuroendocrine lesions (carcinoids) and PETs may need to be classified as two distinct entities rather than grouped together as the single entity "GEP-NETs."
Carcinoid tumors have been reported in a wide range of organs but most frequently involve the gastrointestinal tract; however, duodenal carcinoid tumors are rare. We report a 50-year-old male patient complaining of multiple melenas for 3 wk. The panendoscopy and endoscopic retrograde cholangiopancreaticography revealed swelling accessory papilla with an ulcer. The biopsy taken showed a carcinoid tumor. The lesion was removed by wide resection. Patient was found to have an abnormal blood cell count during the follow-up period with elevated levels of hemoglobin and hematocrit of 21.2 g/dL and 63.5%, respectively, thrombocytosis of 501,000/microL, and leukocytosis of 20,410/microL. He was diagnosed as a polycythemia vera by a hematologist after further evaluation. He received periodic phlebotomy and hydroxyurea treatment. The response was good and his hematocrit was stabilized by periodic phlebotomy in the range of 44-49% during the last 2 years. The possible origin of UGI bleeding by a duodenal carcinoid tumor, although rare, should be considered. There has been one case report of a duodenal carcinoid tumor that involved accessory papilla of the pancreas divisum and one case report of metastatic carcinoid tumor associated with polycythemia vera. It is different in our patient as compared with the latter report, which mentioned a polycythemia vera patient who was found to have a metastatic carcinoid in the 17 years follow-up period. Chemotherapy had been given before the carcinoid tumor was revealed. Our patient had no previous chemotherapy for polycythemia vera before he was found to have duodenal carcinoid tumor; this excludes the possibility of chemotherapy induced carcinoid tumor, although it had been suspected in the previous report. In our patient, the existence of both diseases may be by predisposition of each other since both diseases have an increased incidence of other neoplasm, or they may be coexistent incidentally.
Pulmonary carcinoids are rare neuroendocrine tumors which comprise 1-2% of all lung tumors. They usually occur sporadically; however, their association with multiple endocrine neoplasia type 1 (MEN1) syndrome has been documented. We report a case of a Thai woman with a pulmonary carcinoid tumor and a null cell pituitary tumor. Her family history was unremarkable for any MEN-related lesions. Genetic testing revealed a novel deletion mutation at exon 10 (1793delG) of the MEN1 gene, resulting in a stop codon 26 amino acids downstream. This mutation is predicted to cause a loss of the second nuclear localization signal of the menin protein.