Answer:

Other manifestations of lung tumors are primarily related to mass effects or altered metabolism. In addition to bronchial obstruction (evident in this patient) occasionally leading to postobstructive pneumonia, mass effects include invasion into the chest wall and pleura, compression of great vessels (e.g., superior vena cava syndrome) and heart, tracheobronchial displacement, and/or paresis of the recurrent laryngeal or phrenic nerves and the sympathetic chain. Pancoast syndrome can present with pain and upper extremity weakness secondary to invasion of the brachial plexus as well as the first and second thoracic and eighth cervical nerve roots. Recognized metabolic manifestations of small cell lung tumors include symptoms resembling those of Cushing syndrome (from ectopic adrenocorticotropic hormone production), carcinoid syndrome, hypercalcemia and hypophosphatemia (resulting from ectopic parathyroid hormone or parathyroid hormone-related peptides), hypokalemia (caused by ectopic adrenocorticotropic hormone secretion), and hyponatremia (from inappropriate secretion of antidiuretic hormone and possibly atrial natriuretic factor). Neurologic paraneoplastic syndromes include Eaton-Lambert myasthenic syndrome, peripheral motor and sensory neuritis, cerebellar degeneration, retinopathy, limbic encephalopathy, and autonomic neuropathy. An autoimmune process has been suggested for these findings, and it seems to be more common in patients with limited disease.

Extrathoracic spread of the tumor can affect the bones, liver, adrenal glands, intra-abdominal and subcutaneous lymph nodes, brain, and spinal cord, contributing to the nonspecific presentation of the cancer.

• Ettinger DS, Wood DE, Aisner DL, et al. Non-small cell lung cancer, version 5.2017, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2017;15:504-535.
• Kritek PA, Levy BD. Approach to the patient with disease of the respiratory system. In: Jameson JL, Fauci AS, Kasper DL, et al, eds. Harrison’s Principles of Internal Medicine. 20th ed. New York: McGraw-Hill; 2018:278.