Plasma cell dyscrasia with marrow fibrosis. Clinicopathologic syndrome.

Five new cases of plasma cell dyscrasia with coexistent myelofibrosis are described and six previously reported cases are reviewed. Four of the new patients and two from the literature had features of a previously unrecognized syndrome. This syndrome was characterized by significant paraprotein levels, marked marrow fibrosis, and plasmacytosis, without features of extramedullary hematopoiesis (agnogenic myeloid metaplasia) and leukoerythroblastosis. These patients were generally severely anemic and commonly leukopenic and thrombocytopenic. In contrast, one of the new patients and four in the literature showed classic features of the myeloproliferative disease, myelofibrosis with agnogenic myeloid metaplasia, along with features of typical multiple myeloma.