All Sample Questions

Paraneoplastic Syndromes 1

Question

Vignette: A 60-year-old male with a history of heavy smoking presents to the clinic with a persistent cough, weight loss, and shortness of breath. Physical examination reveals clubbing of the fingers. Chest X-ray shows a large mass in the right upper lobe of the lung with mediastinal lymphadenopathy. Biopsy of the mass reveals small cells with hyperchromatic nuclei and scant cytoplasm.

Question: Which of the following paraneoplastic syndromes is most likely to be associated with the patient's cancer?

Choices

A) Hypercalcemia

B) Cushing's syndrome

C) Syndrome of inappropriate antidiuretic hormone (SIADH)

D) Hypoglycemia

E) Polycythemia

Answer

C) Syndrome of inappropriate antidiuretic hormone (SIADH)

Explanation

This patient's history of heavy smoking, present symptoms, and biopsy findings suggest a diagnosis of small cell lung carcinoma (SCLC). SCLC is one of the most aggressive types of lung cancer and is strongly associated with smoking. One of the hallmarks of SCLC is the ability to secrete ectopic hormones leading to paraneoplastic syndromes. The most common paraneoplastic syndrome associated with SCLC is the syndrome of inappropriate antidiuretic hormone secretion (SIADH), which results from the tumor's ectopic production of antidiuretic hormone (ADH). This leads to water retention and hyponatremia. Other paraneoplastic syndromes associated with SCLC include cushing's syndrome due to ectopic ACTH production and Lambert-Eaton syndrome due to the production of antibodies against presynaptic calcium channels.