Do cytogenetic abnormalities precede morphologic abnormalities in a developing malignant condition?

Cytogenetic evaluation of bone marrow and neoplastic tissues plays a critical role in determining patient management and prognosis. Here, we highlight two cases in which the cytogenetic studies challenge the common practice of using hematologic and morphologic changes as key factors in malignant disease management. The first case is that of a lymph node sample from a 40-yr-old non-Hodgkin's lymphoma (NHL) patient sent for determination of disease progress. Hematologic studies showed no evidence of transformation to high-grade NHL (>15% blasts with rare mitotic figures). Cytogenetic studies of lymph node showed multiple clonal abnormalities, most notably a der(18) from a t(14;18) which is associated with high-grade NHL. After two cycles of chemotherapy with fludarabine, the patient did not show any clinical response, suggesting possible progression to high-grade lymphoma. The second case is of a patient with a history of human immunodeficiency virus and blastic natural killer leukemia/lymphoma. Hematologic studies of ascitic fluid classified the patient as having pleural effusion lymphoma whereas bone marrow analysis showed no malignancy. Bone marrow cytogenetic studies showed multiple clonal abnormalities including a t(8;14), which is commonly associated with Burkitt's lymphoma (BL). To our knowledge, this is the first case wherein a morphologically normal bone marrow showed presence of clonal abnormalities consistent with BL or Pleural effusion lymphoma. After two cycles of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy, the patient's general condition and ascitis improved and she was discharged. These studies clearly demonstrate that genetic changes often precede morphologic changes in a developing malignant condition. Therefore, the critical information needed for care of patients with malignant disorders may be incomplete or inaccurate if cytogenetic evaluation is overlooked.