A Case of Cutaneous Extramedullary Hematopoiesis Associated with Idiopathic Myelofibrosis

Cutaneous Myelofibrosis With JAK2 V617F Mutation: Metastasis, Not Merely Extramedullary Hematopoiesis!

“…Such involvement is usually described in the literature as ''extramedullary hematopoiesis.'' 3,4 During embryogenesis, hematopoiesis occurs mainly in the liver, with contributions from the bone marrow, thymus, spleen, and lymph nodes. EMH describes production of blood elements outside the marrow as seen in the liver during embryogenesis.…”

“…12 Although PMF is now classified as a malignant neoplasm, involvement outside the marrow is still usually reported as EMH. 3,4 Hickling 13 described the first case of cutaneous involvement by myelofibrosis in 1937. He reported a series of patients with myelofibrosis, one of whom developed ''raised pink patches,'' especially over the abdomen.…”

“…Since then, 31 cases have been reported. 3,4 Most cases are reported as EMH, although in 1992, Hoss and McNutt 10 suggested the term ''cutaneous myelofibrosis'' because they believed that the cutaneous lesions recapitulated the morphology of PMF rather than representing reversion to fetal erythropoiesis. In 2007, O'Malley 11 suggested ''neoplastic myeloid proliferation'' instead of EMH to describe extramedullary proliferations of hematopoietic elements in patients with an underlying myeloid neoplasm.…”

“…Thirty-one cases of CMF have been described in the literature, usually as EMH. 3,4 The dermal erythropoiesis seen in the ''blueberry muffin'' baby syndrome caused by intrauterine infections and hemoglobinopathies is also described in the literature as EMH but has an entirely different pathogenesis, clinical presentation, and histopathology. 5,6 EMH has also been described in adults without an underlying hematologic disorder.…”

“…However, cases of CMF continue to be reported as EMH. 3,4 CASE REPORT An 82-year-old white man presented with a 3-day history of dermal and subcutaneous nodules across his chest. His medical history was significant for a 5-year history of PMF, being treated with hydroxyurea (500 mg/day).…”