High serum levels of lactic dehydrogenase identify a high-grade lymphoma-like myeloma. Ann Intern Med 110: 521–525

Although conferring a grave prognosis in patients with ma-lignant lymphoma, high levels of serum lactic dehydroge-nase (LDH) are usually not seen in patients with multiple myeloma, a more indolent tumor composed mainly of B cells in their terminal stage of differentiation. Thus, only 2 of 118 patients in earlier phases of myeloma showed marked LDH elevations to more than 500 U/L, whereas such abnormalities were present in 12 of 64 patients with ad-vanced disease progressing despite treatment with vin-cristine, doxorubicin (Adriamycin), dexamethasone (VAD) (median LDH level, 700 U/L). High LDH levels were associated with high serum levels of beta-2-microglobu-lin, hypercalcemia, extraosseous disease features, a short preceding clinical course as well as a short subsequent sur-vival time. A poor prognosis was also noted in patients wit