A 46-year-old man presented with a 1-year history of painful lesions on his right foot that caused difficulty with ambulation. The lesions had slowly enlarged, and nonpainful lesions subsequently developed on his right leg and abdomen. He denied fevers, chills, weight loss, fatigue, or other systemic complaints. Physical examination revealed multiple soft, violaceous nodules on the right sole, with extension to the great toe and medial malleolus (Figure 1). The nodules were tender to palpation. Similar-appearing nontender nodules were found in the right popliteal fossa. Two nontender, violaceous, compressible nodules were also evident on the right side of the abdomen (Figure 2). There was no lymphadenopathy or hepatosplenomegaly. Biopsy specimens were obtained from the right popliteal fossa and the abdomen (Figure 3 and Figure 4). Histopathologic sections revealed the same process in both specimens. Cultures were negative for fungi and acidfast bacilli. What is your diagnosis?