What is Which of the following in an example of an amine precursor uptake and decarboxylation (APUD) type of tumor in the lung? and explain in detail?
A bronchial carcinoid is an example of an amine precursor uptake and decarboxylation (APUD) tumor or neuroendocrine tumor. This name is applied to ceain cells of the endocrine organs (e.g., anterior pituitary, pancreatic islets, C-cells in the thyroid, adrenal medulla, paraganglia) as well as single cells in various tissues (e.g., Kulchitsky's cells in the bronchial epithelium, argentaffin cells in the gut). APUD tumors are thought to have a common derivation from neural crest and neuroectoderm, thus the appellation, neuroendocrine tumors. However, there are some APUD tumors of endodermal origin. These tumors have dense core neurosecretory granules present on electron microscopy. Tumors involving these cells can be adenomas or carcinomas. They are characterized by the production of various polypeptide hormones that have either a local paracrine effect (e.g., bombesin, vaso intestinal peptide or a more generalized effect. Ref - Harrison's principles of internal medicine 20e pg 596-598,264 Squamous cell carcinoma and adenocarcinoma are of epithelial origin. Bronchial hamaomas are not neoplastic and are an exaggerated overgrowth of tissue normally present in that organ. Bronchioloalveolar carcinomas are derived from mucin-secreting bronchiolar cells, Clara cells, or type II pneumocytes.