A 50 year old male presents with the strange skin finding shown above. It began as erythematous plaques on the face, perineum, and extremities, but over the last week or two, the lesions have become larger and confluent. There's some central clearing, leaving bronze indurated central areas with blistering, crusting, and scaling at the borders. The lesion is pruritic and painful.
The patient also complains of weight loss, sore lips, and abdominal pain. The chart notes a recent diagnoses of venous thrombosis, diabetes mellitus, and neuropsychiatric changes. HbA1C is 9.8. The patient has a normochromic, normocytic anemia.
Challenge: Assuming all the findings here are due to one cause, what does the patient have?
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