Lung Cancer : Small cell carcinoma

• This is a highly malignant tumour, with lymphocyte looking cells (twice the size of lymphocytes) – accounts for about 30% of lung cancer cases. They have little cytoplasm (i.e.: histologically basophilic). The cells grown in clusters.
  
• Electron microscopic studies show dense neurosecretory granules in some of these cells, and these granules are similar to those found in the neuroendocrine cells lining the bronchial epithelium.
  
• Also some cells exhibit presence of neuroendocrine markers such as: neuron-specific enolase and parathormone like active products. This suggests that these tumours have a origin from neuroendocrine cells lining the bronchial epithelium.
  
• Small cell carcinomas have strong relationship to smoking, only 1% of non-smokers get it. They are usually located centrally in the hilar region.
• They metastasize rapidly, so surgical repair is not possible – chemotherapy is best. This sort of a tumour is commonly associated with a paraneoplastic syndrome (i.e.: especially if it produces ACTH & ADH)

Category: Pathology Notes