Cytodiagnosis of primary lymphoma of bone on fine-needle aspiration cytology specimens: review of 25 cases

Diagnosis of nodal lymphomas on fine-needle aspiration (FNA) cytologic specimens has been well established. However, cytodiagnosis of primary lymphoma of bone has not been well documented because of its rarity. We undertook a retrospective study of 25 cases of FNA cytologic specimens of primary lymphoma of bone. The slides were available for review in 20 cases; each case was evaluated with 15 cytologic features in conjunction with immunophenotyping and available surgical materials. Three diagnostic categories were assigned, including nondiagnostic (4/16%), suspicious (3/12%), and malignant (18/72%). Among the 18 malignant lymphoma, all were diagnosed on the basis of cytologic materials together with immunocytochemistry, except that two cases also relied on the cell blocks. The nondiagnostic and suspicious cases were subsequently confirmed to be malignant lymphoma on the surgical core biopsies. Of the 25 cases, 23 cases were large B-cell lymphoma, one follicular lymphoma large cell type, and one small lymphocytic lymphoma. False-positive or false-negative cases were not present in this study series. In conclusion, the vast majority of primary lymphoma of bone can be accurately diagnosed and classified on FNA cytologic specimens in conjunction with immunocytochemistry. The nondiagnostic and suspicious categories can be further reduced or eliminated by improving FNA techniques or by recommendation of surgical core biopsies together with other techniques such as flow cytometry and molecular analysis.