Question of the Week

For March 19, 2019

An 82-year-old woman is brought to the clinic by her husband, who reports that she has been disoriented for several days and is unable to recognize him. He reports that her cognition was completely intact a week ago. The patient’s medical history is significant for hypertension, well-controlled type 2 diabetes, and hyperlipidemia. Her daily medications include amlodipine 10 mg, metformin 500 mg, and simvastatin 20 mg.

She reports a 60-pack-year history of cigarette smoking and denies any history of alcohol or illicit drug use. Ten years ago, she retired from her job working as a manager of a steel mill, where she believes that she may have been exposed to asbestos.

Her physical examination is unremarkable, with the exception of diffuse wheezes in all lung fields and a barrel chest. She is oriented only to her name, but her neurological examination is otherwise normal.

Laboratory testing yields the following results:

Patient value

Reference range

Sodium (mEq/liter)

139

136–145

Blood urea nitrogen (mg/dL)

13

10–20

Creatinine (mg/dL)

0.7

0.6–1.1

Glucose (mg/dL)

102

70–100

Calcium (mg/dL)

14.4

9.0–10.5

Ionized calcium (mg/dL)

7.0

4.5–5.6

Albumin (g/dL)

3.6

3.5–5.5

Parathyroid hormone (pg/mL)

3

10–60

An MRI of the head shows no evidence of ischemia or tumors. A chest radiograph reveals a 4.3-cm mass in the center of her right lung. Further workup for other sites of suspected malignancy is negative.

Which one of the following types of cancer is the most likely cause of this patient’s presentation?

Mesothelioma
Squamous-cell carcinoma of the lung
Small-cell lung cancer
Thymoma
Adenocarcinoma of the lung