A 60-year-old man presents to a free clinic for evaluation of a “knot” in his left lower axilla. He first noticed it several months ago. Even though the lesion grew, the patient reasoned that it couldn’t be too serious since “it didn’t hurt.” But in the past month, the lesion has become much more firm and darkened.
The patient denies any other health problems. He has an 80-pack-year history of smoking. He has never had health insurance and as a result has carefully avoided any interaction with the health care establishment.
Additional history-taking reveals that he has become markedly short of breath in the past few months, which he attributes to his smoking. He denies any abdominal pain or headache. As a young man, he spent 20 years working as a roofer, often going shirtless in hot weather.
EXAMINATION
The patient is in no distress. He is accompanied by his wife, who participates in the history-taking process. Both call attention to the lesion in question, a 5.5-cm dark subcutaneous mass in the left lower axilla. The overlying skin is dark as well, and on palpation, the mass is found to be fixed and firm. Palpation elsewhere in the axillae, as well as in the head and neck, fails to detect any other lesions.
The rest of the patient's type III skin (easily tanned, seldom burned) shows limited evidence of sun damage. A few minor solar lentigines are seen on the trunk, but none stand out. Then the patient's wife points out a barely discernible, depigmented, poorly defined macule on the left lateral back. It measures about 2 cm. This lesion, she reports, "used to be real black. Then it turned scabby, and then it lost all its color. It's been this way ever since."
Continue reading for the diagnostic studies...