A progressively growing lesion on the left knee prompted a 35-year-old woman to visit our clinic. She reported that about 3 months earlier, she had developed a small ulceration on the knee following a fall. With local wound care, the ulceration healed with a scar. The scar, however, continued to grow and she developed distinct papules outside the original scar.
FIGURE
Scar develops into a dusky plaque
The scar subsequently became raised with violaceous discoloration. The patient reported having no history of excessive scarring or keloid forming after skin surgery or trauma. There was neither a personal nor family history of inflammatory or infectious granulomatous diseases.
On physical examination, there was an erythematous to dusky plaque with well-defined irregular borders. There were also discrete papules on the anterior and medial aspect of the knee. The plaque measured approximately 2.8 cm by 3.8 cm. There were no tender nodules on the shins, nor was lymphadenopathy present. A routine chest x-ray was normal.
To support our clinical diagnosis, we took a 4-mm punch biopsy from the center of the plaque. The histologic examination revealed changes in the dermis termed noncaseating “naked” granulomas.
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