Erythematous papulonodules that resembled a malignant lymphoma developed in a 62-year-old man. Further examination revealed that he had primary myelofibrosis with cutaneous extramedullary hematopoiesis. All three marrow elements (myeloid, erythroid, and mega-karyocytic series) were present in the skin lesions. Although extramedullary hematopoiesis of the skin is a rare complication of myelofibrosis, 13 similar cases have been reported. In nine cases, including ours, all three marrow elements were present in the cutaneous lesions. © 1990, American Academy of Dermatology, Inc.. All rights reserved.