Background. The authors devised a histopathologic classification system for interpreting bone marrow biopsy materials in patients with mycosis fungoides and the Sézary syndrome and correlated histopathologic findings with clinical stage and outcome.
Methods. Bone marrow specimens from 90 consecutively staged patients were examined for lymphoid infiltrates, benign or cytologically atypical lymphoid aggregates, and large or cytologically transformed cells.
Results. Thirty-seven (41%) marrows were involved, two with diffuse lymphomatous infiltrates and 35 with lymphoid aggregates. Twelve of the 35 had lymphoid aggregates consisting of cytologically normal-appearing lymphocytes, and 23 had aggregates composed of cytologically atypical lymphocytes. Eleven patients had greater than 5% large cytologically transformed cells. Patients with infiltrative disease or cytologically atypical aggregates had an inferior survival compared with those with cytologically normal lymphocytes (P2 = 0.0042), and patients with aggregates consisting of cytologically normal lymphocytes had a survival comparable with that of patients with uninvolved marrows (P2 = 0.33). Whereas most patients with cytologically atypical marrows had advanced skin and lymph node involvement, 28% had early skin stage. Bone marrow eosinophilia was noticed in 38% of patients and was not consistently associated with peripheral blood eosinophilia or clinical stage.
Conclusions. These results suggest that patients with cytologically atypical lymphoid aggregates or diffuse lymphomatous infiltration of the marrow have an inferior survival regardless of clinical stage, whereas those with lymphoid aggregates consisting of cytologically normal-appearing lymphocytes have a survival indistinguishable from that of patients without lymphoid aggregates.