What are the extrapulmonary symptoms of lung cancer? There are three main manifestations of extrapulmonary symptoms of lung cancer

I believe everyone knows what lung cancer is and the symptoms related to lung cancer. But do you know about extrapulmonary symptoms? Do you know what these symptoms mean? Extrapulmonary symptoms are some symptoms of other organs of the body before lung cancer. These symptoms may be signs of lung cancer, so understanding extrapulmonary symptoms is very helpful for the prevention of lung cancer.

What are the extrapulmonary symptoms of lung cancer?

Due to certain special active substances produced by lung cancer (including hormones, antigens, enzymes, etc.), patients may experience one or more extrapulmonary symptoms, which often appear before other symptoms and may disappear with the growth and decline of the tumor. Pulmonary osteoarthritis is more common clinically.

1. Pulmonary osteoarthritis

Clinically, the main manifestations are tussock fingers (toes), periosteal hyperplasia at the distal end of long bones, new bone formation, swelling, pain and tenderness in the affected joints. The long bones are the tibia, humerus and metacarpal bones, and the joints are more common in large joints such as the knee, ankle and wrist. The incidence of tussock fingers and toes is about 29%, which is mainly seen in squamous cell carcinoma; the incidence of hyperplastic osteoarthritis is 1% to 10%, which is mainly seen in adenocarcinoma, and small cell carcinoma rarely has this manifestation. The exact cause is not yet fully understood, and it may be related to estrogen, growth hormone or nerve function. Surgical resection of the tumor can relieve or disappear, and it may recur when it recurs.

2. Ectopic hormone secretion syndrome associated with tumors

About 10% of patients may experience such symptoms, which may appear as the first symptom. Some other patients may have no clinical symptoms, but one or more plasma ectopic hormones may be detected to be elevated. Such symptoms are more common in small cell lung cancer.

(1) Ectopic adrenocorticotropic hormone (ACTH) secretion syndrome. The tumor secretes ACTH or adrenocorticotropic hormone-releasing factor-like active substances, which increases plasma cortisol. The clinical symptoms are similar to those of Cushing's syndrome, and may include progressive muscle weakness, peripheral edema, hypertension, diabetes, hypokalemic alkalosis, etc. It is characterized by rapid progression of the disease, severe mental disorders, and skin pigmentation, while central obesity, polycythemia, and purple striae are not obvious. This syndrome is more common in lung adenocarcinoma and small cell lung cancer.

(2) Ectopic gonadotropin syndrome is caused by the tumor's autonomous secretion of LH and HCG, which stimulates the secretion of gonadal steroids. It is often manifested as bilateral or unilateral breast development in men. It can occur in lung cancer of various cell types, with undifferentiated carcinoma and small cell carcinoma being the most common. Occasionally, abnormal penile erection can be seen, which is related to abnormal hormone secretion and may also be caused by penile vascular embolism.

(3) Ectopic parathyroid hormone syndrome is caused by tumor secretion of parathyroid hormone or an osteolytic substance (peptide). Clinically, it is characterized by hypercalcemia and hypophosphatemia, and symptoms include loss of appetite, nausea, vomiting, abdominal pain, thirst, weight loss, tachycardia, arrhythmia, irritability and mental confusion. It is more common in squamous cell carcinoma.

(4) Ectopic insulin secretion syndrome is clinically manifested by subacute hypoglycemia symptoms, such as mental confusion, hallucinations, headaches, etc. The cause may be related to the tumor consuming a large amount of glucose, secreting body fluid substances with insulin-like activity, or secreting insulin-releasing polypeptides.

(5) Carcinoid syndrome is caused by the secretion of 5-hydroxytryptamine by the tumor. It manifests as bronchospasmodic asthma, skin flushing, paroxysmal tachycardia, and watery diarrhea. It is more common in adenocarcinoma and oat cell carcinoma.

(6) Neuromuscular syndrome (Eaton-Lambert syndrome) is caused by the secretion of arrow-like substances by the tumor. It is manifested as voluntary muscle weakness and extreme fatigue, which is common in small cell undifferentiated carcinoma. Other symptoms include peripheral neuropathy, spinal root ganglion cell and nerve degeneration, subacute cerebellar degeneration, cortical degeneration, polymyositis, etc., which may cause pain and weakness in the extremities, dizziness, nystagmus, ataxia, difficulty walking, and dementia.

3. Other manifestations

(1) Skin lesions Acanthosis nigricans and dermatitis are more common in adenocarcinoma, while skin pigmentation is caused by the secretion of melanocyte stimulating hormone (MSH) by the tumor and is more common in small cell carcinoma. Other skin lesions include scleroderma and palmoplantar hyperkeratosis.

(2) Cardiovascular system: All types of lung cancer may cause abnormal coagulation mechanisms, resulting in migratory venous thrombosis, phlebitis, and non-bacterial embolic endocarditis, which may occur several months before the diagnosis of lung cancer.

(3) Hematological system symptoms include chronic anemia, purpura, erythrocytosis, and leukemoid reactions. These symptoms may be caused by reduced iron absorption, shortened life span due to erythropoiesis disorders, capillary osmotic anemia, etc. In addition, DIC may occur in lung cancers of various cell types, which may be related to the release of procoagulant factors by the tumor. Patients with squamous cell lung cancer may also have purpura.