Case for diagnosis. Hyperpigmented and excoriated papules and nodules in a diabetic patient.

Reactive perforating collagenosis is a rare perforating dermatosis clinically characterized by intensely pruritic hyperpigmented papules, plaques, and nodules with a central keratotic plug. Histopathology reveals transepidermal elimination of collagen fibers. Its pathophysiology is still under investigation, but the acquired form has been linked to systemic conditions such as diabetes mellitus and chronic kidney disease. However, it has also been described as a paraneoplastic syndrome. The authors present the case of a 65-year-old diabetic patient in which a myeloproliferative neoplasm was suspected.