Definition of small cell lung cancer

What is the definition of small cell lung cancer? Most people don't know much about this disease, but they feel terrified when they hear it is cancer. They think cancer is a disease that cannot be cured and lose confidence in life. So, let's understand the definition of small cell lung cancer together!

Smoking is the main risk factor for small cell lung cancer, and SCLC is closely related to smoking. According to a summary analysis of smoking and lung cancer worldwide from 1970 to 1999, small cell lung cancer is positively correlated with smoking intensity (amount of smoking) and duration, and the relationship with SCLC is most obvious.

1. Symptoms and signs caused by the primary tumor

(I) Cough: It is a common early symptom, mostly irritating dry cough. When the tumor causes bronchial stenosis, a persistent, high-pitched metallic cough may occur. Cough is often accompanied by a small amount of mucus sputum, and when secondary infection occurs, it may be combined with purulent sputum.

(ii) Hemoptysis: Most cases are blood in the sputum or intermittent bloody sputum. In a few cases, severe hemoptysis occurs due to erosion of large blood vessels.

(III) Chest tightness and shortness of breath: The tumor causes bronchial stenosis, or the tumor metastasizes to the hilar or mediastinal lymph nodes, and the enlarged lymph nodes compress the main bronchus or tracheal carina.

It is generally believed that small cell lung cancer originates from Kulchitsky cells (argentophilic cells) in the bronchial mucosa or glandular epithelium and is an APUD (amine precursor uptake decarboxylation) tumor. Some people also believe that it originates from stem cells in the bronchial mucosal epithelium that can differentiate into neuroendocrine.

Small cell lung cancer is the least differentiated and most malignant type of lung cancer. It often occurs in the central part of the lung, grows rapidly, and metastasizes early. Under a light microscope, the cancer cells are small and short spindle-shaped or lymphocyte-like, with little cytoplasm and a naked nucleus. Cancer cells are densely arranged in groups, separated by connective tissue, and sometimes cancer cells are arranged in groups around small blood vessels. Electron microscopic observation of the ultrastructure shows that the tumor cell cytoplasm contains typical axon-like neuroendocrine granules, but the amount of granules varies, and it has been shown to be related to 5-HT and ACTH.