What Explains This Man’s Nail Discoloration?

AUTHORS:
Abhinav Talwar
BS/MD Student, Northwestern University Feinberg School of Medicine, Chicago, Illinois

Ankoor Talwar
BS/MBA/MD Student, Union College/Albany Medical College, Albany, New York

Sonia A. Talwar, MD
Chief of Endocrinology, North Shore University Hospital at Plainview, New York

CITATION:
Talwar A, Talwar A, Talwar SA. What explains this man’s nail discoloration? [published online January 20, 2020]. Consultant360.

A 69-year-old man was evaluated at an outpatient clinic for his type 2 diabetes mellitus. The man is a retired construction worker with a history of hypercholesterolemia, hypertension, and essential thrombocythemia. He denied any history of arterial or venous thrombosis.

Physical examination findings and vital signs were unremarkable except for the patient’s hands, which showed multiple longitudinal brown-black pigmented bands on some of the fingernails bilaterally (Figure). His nails also appeared thickened, which he ascribed to his profession. The patient had noticed the nail discoloration for many years but had paid no attention to it. His toenails were not affected, and no other mucocutaneous pigmentations were seen. He was on aspirin, metoprolol, metformin, and hydroxyurea, the latter at a dosage of 500 mg/day for the past 1 year. Results of all routine laboratory investigations were normal except for mild anemia (hemoglobin, 12.8 g/dL; platelet count, 300 × 10³/µL). A biopsy was deemed unnecessary.

What is the cause of this man’s brownish nail discoloration?

A. Pseudomonas aeruginosa infection

B. Hydroxyurea-induced melanonychia

C. Subungual melanoma

D. Subungual hematoma