Neoplasia

Question 1

What is paraneoplastic syndrome? What are the main types of paraneoplastic syndrome? By what mechanism can paraneoplastic syndrome occur? What is the cause of cachexia in cancer? By

Answer 1

1. Paraneoplastic syndrome is
   - Cluster of symptoms that cannot be explained by tumor itself or local/distant spread of tumor
   - Caused by secretion of tumor elsewhere
2. Types of paraneoplastic syndrome
   A. Hormonal
   - SIADH -> Secretes ADH -> Hyponatremia, Na and water retention -> Small cell lung cancer
   - Cushing’s -> Secretes ACTH -> Small cell lung cancer
   - Parathyroid -> Secretes PTH -> Hypercalcemia -> Small cell lung cancer, breast cancer
   - Carcinoid syndrome -> Secretes serotonin, bradykinin -> Pancreatic cancer, stomach cancer
   B. Nerve Syndrome
   - Myaesthenia gravis -> Bronchogenic CA
   C. Dermatological
   - Acanthosis nigrigans
   D. MSK
   - Hypertrophic pulmonary osteoarthropathy
3. Mechanisms causing paraneoplastic syndrome
   - Hormone production -> SIADH, ACTH, PTH, Carcinoid
   - Immunologic -> Myaesthenia gravis
   - Tumour antigens -> HPOA, Acanthosis nigrigans
4. Mechanism of cachexia in cancer is generally unknown
   - High basal metabolic rate
   - Anorexia
   - Tumor producing hormone/factors