Skin Deep

A CLINICAL PROBLEM-SOLVING article by Nasia Safdar from the University of Wisconsin–Madison School of Medicine.
A 56-year-old woman with symptoms of carpal tunnel syndrome for 6 months presented to a referral clinic with nodular lesions on her right forearm and hand and an increase in numbness and tingling in her right hand.
During the previous 3 months, the patient had several appointments with an orthopedic surgeon for carpal tunnel syndrome. The surgeon performed an incision and drainage on one of the forearm lesions, and serosanguineous fluid was noted. Over the next 2 weeks, new lesions formed on the dorsum of her hand and on the palmar side at the base of the middle finger. A carpal-tunnel–release procedure was then performed on the right side. Pathological assessment of biopsy specimens obtained during the procedure revealed granulomas with central necrosis and predominant neutrophilic infiltration. Gram's stain and special stains were negative for bacteria, mycobacteria, and fungi.
She had annual tuberculin skin tests at her job at a medical clinic; after 13 years of negative tests, her most recent test 3 weeks earlier was positive, with 11 mm of induration; a chest radiograph was negative. The patient lived in the midwestern United States. She recalled injuring her thumb on a thorn on a separate occasion approximately 4 months before the nodular lesions appeared.
On current physical examination, the volar aspect of her right arm had a 6-cm surgical incision, with a violaceous area surrounding it.
In this case, the positive tuberculin test provided an important clue.
[Original Article]