A 65-year-old healthy woman without a significant medical history presented for a routine skin examination. Her dermatologic history was remarkable only for a basal cell carcinoma of the face that had been treated 13 years earlier. She had no known family history of skin cancer.
On physical examination, a slightly erythematous, firm papule with a faint, tan area at the periphery was found on the right upper arm area (Figure 1). The papule was roughly symmetrical, had well-demarcated borders, and measured 7 × 6 mm. Palpation of the lateral edges of the lesion demonstrated induration. There was no history of rapid growth, pruritus, bleeding, or recent change. The patient was unsure of the lesion’s duration and attributed it to a possible scar from an insect bite.
Zand S, Lio PA, Mackool BT, Duncan LM. A Slightly Erythematous, Firm Papule on the Upper Arm—Quiz Case. Arch Dermatol. 2005;141(1):93-98. doi:10.1001/archderm.141.1.93-e