PRIMARY MEDIASTINAL LARGE-CELL LYMPHOMA IS CHARACTERIZED BY AN INVERTED PATTERN OF LARGE TUMORAL MASS AND LOW BETA(2) MICROGLOBULIN LEVELS IN SERUM AND FREQUENTLY ELEVATED LEVELS OF SERUM LACTATE-DEHYDROGENASE

Background: Primary mediastinal large cell lymphoma (PMLCL) is an emer ging entity. New parameters can help define it. Materials and methods: Retrospective analysis of medical records from 35 patients treated at The University of Texas M.D. Anderson Cancer Center from 1985 to 1990 . Immunohistochemical evaluation of tissue specimens. Determination of survival (S) and time to treatment failure (TTF). Results: The median age was 34 years and 69% were females. Eighty-three percent presented with symptoms of mediastinal involvement. While 100% of the patients presented with bulky mediastinal disease and 72% had elevated pretreat ment serum lactate dehydrogenase, only 6% presented with an elevated p retreatment serum beta(2) microglobulin. The lymphoma cells lacked CD2 1 staining. For the 18 patients treated initially at M.D. Anderson Can cer Center, S and TTF curves rates after doxorubicin-based regimens (p lus radiotherapy in 14 cases) were 72% and 61%, respectively, at 5 yea rs follow-up (median, 42 months). Four out of six patients who receive d autologous bone marrow transplant as salvage therapy are currently a live without disease at followup times of 21, 25, 32, and 54 months. C onclusion: Primary mediastinal large cell lymphoma has characteristic clinicopathological features to which another can be added, that of an inverted pattern of bulky disease, high LDH and low beta(2)M in serum . The response to therapy is comparable to that of intermediate-grade lymphomas, although the numbers in the study are small. Our preliminar y data suggest a possible role for autologous bone marrow transplantat ion (ABMT) as salvage therapy.