Primary mediastinal large cell lymphoma is characterized by an inverted pattern of large tumoral mass and low β₂ microglobulin levels in serum and frequently elevated levels of serum lactate dehydrogenase

Background: Primary mediastinal large cell lymphoma (PMLCL) is an emerging 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 pretreatment serum lactate dehydrogenase, only 6% presented with an elevated pretreatment serum β₂ microglobulin. The lymphoma cells lacked CD21 staining. For the 18 patients treated initially at M.D. Anderson Cancer Center, S and TTF curves rates after doxorubicin-based regimens (plus radiotherapy in 14 cases) were 72% and 61%, respectively, at 5 years follow-up (median, 42 months). Four out of six patients who received autologous bone marrow transplant as salvage therapy are currently alive without disease at follow-up times of 21, 25, 32, and 54 months. Conclusions: 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 β₂M in serum. The response to therapy is comparable to that of intermediate-grade lymphomas, although the numbers in the study are small. Our preliminary data suggest a possible role for autologous bone marrow transplantation (ABMT) as salvage therapy.