Extramedullary hemopoiesis of the skin.
D005335:Fever of Unknown Origin / Q000209:etiology; D006410:Hematopoiesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D055728:Primary Myelofibrosis / Q000473:pathology*; D012867:Skin / Q000473:pathology*; D012871:Skin Diseases / Q000209:etiology