RESUMEN
Posttransplant lymphoproliferative disorders are classified as monomorphic, polymorphic, early lesions, or Hodgkin lymphoma type. Staging bone marrow examination is recommended in posttransplant lymphoproliferative disorder patients; however, information regarding bone marrow involvement in these disorders, especially as related to the posttransplant lymphoproliferative disorder subtype, is scarce. We reviewed the clinicopathologic features of 72 posttransplant lymphoproliferative disorder cases to determine the frequency of bone marrow involvement by various subtypes of posttransplant lymphoproliferative disorder, the clinical features of patients with and without bone marrow involvement, and their outcome. We also compared the incidence of bone marrow involvement of monomorphic posttransplant lymphoproliferative disorder (diffuse large B-cell lymphoma) with de novo diffuse large B-cell lymphoma (in both immunocompetent and HIV+ patients), and assessed the utility of various hematologic and serologic parameters as predictors of bone marrow involvement. Bone marrow involvement was seen in 23.5% of monomorphic posttransplant lymphoproliferative disorders and 15.7% of polymorphic posttransplant lymphoproliferative disorders, and the detection of bone marrow involvement on staging bone marrow biopsy upstaged 42% of monomorphic posttransplant lymphoproliferative disorders and 100% of polymorphic posttransplant lymphoproliferative disorders. Although bone marrow involvement appeared independent of patient age, organ transplanted, Epstein-Barr virus status, interval from transplantation to posttransplant lymphoproliferative disorder, or involvement of the grafted organ, it was significantly more frequent in cases without extranodal involvement; and it was associated with a significantly shorter survival. The incidence of bone marrow involvement in monomorphic posttransplant lymphoproliferative disorder (diffuse large B-cell lymphoma) was similar to that in HIV-associated diffuse large B-cell lymphoma, but higher than that in immunocompetent diffuse large B-cell lymphoma cases. No individual hematologic and serologic parameter was predictive of bone marrow involvement; however, the combination of elevated lactate dehydrogenase (>225 U/L) and decreased hemoglobin (<10 g/DL) can be used as a sensitive screening tool in determining which patients should proceed to bone marrow staging biopsy.