[Cutaneous extramedullary hematopoiesis associated with myelodysplastic/myeloproliferative neoplasm, unclassifiable].

Cutaneous extramedullary hematopoiesis has been reported in a small number of patients with myelofibrosis. A 79-year-old male with JAK2V617F-positive myelodysplastic/myeloproliferative neoplasm, unclassifiable (MDS-MPN-U), presented with multiple skin lesions. The skin lesions were papulonodular, reddish brown, and elastic hard on palpation. Based on a lesion biopsy, cutaneous extramedullary hematopoiesis associated with MDS/MPN-U was diagnosed. He died four months later due to exacerbation of MDS/MPN-U. Cutaneous invasion might be associated with progressive disease and a poor prognosis for MDS/MPN-U, as it is for myelofibrosis.