Clinical Manifestations of Neoplasia | Chapter 7 | ROBBINS PATHOLOGY Based Audio Podcast

Описание: ROBBINS PATHOLOGY
CHAPTER 7 - Neoplasia

Clinical Manifestations of Neoplasia -
Local and Hormonal Effects The clinical impact of a tumor is heavily influenced by its location and functional activity. Even benign tumors can cause significant morbidity.
• Location: Tumors may impinge on vital tissues, causing destruction or impairment. For instance, a benign pituitary adenoma can compress the gland and cause hypopituitarism. Neoplasms in the gut may lead to obstruction or intussusception, though obstruction of bile ducts by pancreatic cancer can sometimes lead to early detection via jaundice. Tumors on natural surfaces often ulcerate, leading to secondary infections and bleeding, such as melena in gastrointestinal cancers or hematuria in urinary tract tumors.
• Hormonal Activity: Neoplasms arising in endocrine glands may produce hormones. This is more common in benign tumors; for example, a small beta-cell adenoma can secrete sufficient insulin to cause fatal hypoglycemia. Nonendocrine tumors may also produce ectopic hormones, leading to paraneoplastic syndromes,.
Cancer Cachexia Cachexia is a debilitating hypercatabolic state affecting about 50% of cancer patients, characterized by profound loss of body fat and lean muscle mass, fatigue, anorexia, and anemia,.
• Mechanism: It is distinct from starvation and is not reversed by food intake. It is driven by inflammatory mediators (e.g., TNF, IL-1, IL-6) released by tumor or immune cells,. These cytokines induce muscle proteolysis, often through the ubiquitin-proteasome pathway. A lipid mobilizing factor likely contributes to fat loss.
• Outcome: Cachexia is responsible for approximately 30% of cancer deaths, often due to atrophy of respiratory muscles like the diaphragm.
Paraneoplastic Syndromes Occurring in roughly 10% of patients, these are symptom complexes not explained by the tumor's local spread or indigenous hormone production. They are clinically critical as they can mimic metastases, cause severe illness, or serve as the earliest sign of an occult cancer.
• Endocrinopathies:
◦ Cushing Syndrome: Caused by ectopic production of ACTH or ACTH-like peptides, most commonly by small-cell lung carcinoma.
◦ Hypercalcemia: The most common paraneoplastic syndrome. It arises via osteolysis (metastasis) or the paraneoplastic production of parathyroid hormone-related protein (PTHRP) by tumors such as squamous cell carcinoma of the lung, breast, and kidney,,.
• Neuromyopathic Syndromes: Conditions like myasthenia gravis, peripheral neuropathies, and cortical cerebellar degeneration may occur. These are likely caused by immunologic cross-reactions where the immune system attacks neuronal antigens expressed ectopically by tumor cells.
• Dermatologic Disorders: Acanthosis nigricans (gray-black hyperkeratotic skin patches) is notably associated with gastric carcinoma.
• Osseous Changes: Hypertrophic osteoarthropathy, involving clubbing of the fingers and periosteal bone formation, is associated with lung carcinoma.
• Vascular and Hematologic Changes: Hypercoagulability is common. Migratory thrombophlebitis (Trousseau syndrome) is often seen with pancreatic or lung cancer, while disseminated intravascular coagulation (DIC) is associated with acute promyelocytic leukemia. Nonbacterial thrombotic endocarditis may also occur.
Analogy: You can think of the clinical manifestations of cancer like a war zone. Local effects are the direct damage from the battle itself (e.g., a bomb destroying a bridge/organ). Cachexia is the rationing and resource depletion that starves the civilian population (the body). Paraneoplastic syndromes are the propaganda or cyber-attacks—remote, systemic disruptions caused by the enemy that create chaos far from the front lines, sometimes before the invasion is even detected.