What is the cause of this soft tissue swelling?

A 12-year-old girl presents with an asymptomatic swelling on the dorsum of her left hand of a few months’ duration. The child is otherwise healthy and has no history of trauma. A radiograph shows only soft tissue swelling.

What is your next step?

A. Order an MRI scan. 

B. Aspirate for deep fungal infection. 

C. Aspirate for atypical mycobacterial infection. 

D. Perform a 3-mm punch biospy. 

E. Perform an excisional biopsy to include muscle.

(Answer on next page)

Answer - Granuloma annulare

This presentation is typical of deep granuloma annulare, an asymptomatic swelling near a joint that frequently
occurs in girls younger than 16 years. A 3-mm punch biopsy, D, confirmed the clinical impression. The lesion resolved in 2 weeks.

The absence of pain and inflammation eliminated an infectious cause. The biopsy encouraged resolution of the granuloma annulare in the patient; these lesions typically resolve spontaneously over months to years. No treatment is necessary.